.gitignore, config, nimble: use lock file (#418)

Before this commit, configlet pinned the version of each Nimble
dependency by using the .nimble file. This was the best approach until
recently, and was good enough for creating configlet releases, but it
wasn't robust [1] - Nimble wasn't designed to produce reproducible
builds with that mechanism. For example, Nimble didn't check the hash
of a package at build time to ensure that it was unmodified.

Now that we've updated to Nim 2.0 [2] and vendored the parseopt3
dependency [3], let's use Nimble's new lock file mechanism. This should
be robust.

Run `nimble lock` and `nimble setup`, and remove versions from the
nimble file.

From the docs for `nimble lock` [4]:

    The `nimble lock` command will generate or update a package
    lock file named `nimble.lock`. This file is used for pinning the
    exact versions of the dependencies of the package. The file is
    intended to be committed and used by other developers to ensure
    that exactly the same version of the dependencies is used by all
    developers.

    [...]

    If a lock file `nimble.lock`` exists, then on performing all Nimble
    commands which require searching for dependencies and downloading
    them in the case they are missing (like `build`, `install`,
    `develop`), it is read and its content is used to download the same
    version of the project dependencies by using the URL, download
    method and VCS revision written in it. The checksum of the
    downloaded package is compared against the one written in the lock
    file. In the case the two checksums are not equal then it will be
    printed error message and the operation will be aborted. Reverse 
    dependencies are added for installed locked dependencies just like
    for any other package being locally installed.

and `nimble setup` [5]:

    The `nimble setup` command creates a `nimble.paths` file containing
    file system paths to the dependencies. It also includes the paths
    file in the `config.nims` file (by creating it if it does not
    already exist) to make them available for the compiler.
    `nimble.paths` file is user-specific and MUST NOT be committed.
    
    The command also adds `nimble.develop` and `nimble.paths` files to
    the `.gitignore` file.`

Closes: #467

[1] d6d7283 ("build: pin versions of Nimble packages", 2021-11-25)
[2] fa7d0bb (".github, config, json, nimble: bump Nim from 1.6.12 to 2.0.0", 2023-08-08)
[3] 7471af3 ("nimble, patches, cli: vendor parseopt3 dependency", 2023-08-08)
[4] https://github.com/nim-lang/nimble/blob/412af022a441/readme.markdown#nimble-lock
[5] https://github.com/nim-lang/nimble/blob/412af022a441/readme.markdown#nimble-setup

.gitignore

@@ -22,3 +22,7 @@
 # Ignore temporary repos
 tests/.test_elixir_track_repo/
 tests/.test_nim_track_repo/
+
+# Ignore user-specific Nimble files
+nimble.develop
+nimble.paths

config.nims

@@ -28,3 +28,11 @@ if defined(release):
     elif defined(clang):
       switch("clang.exe", "musl-clang")
       switch("clang.linkerexe", "musl-clang")
+
+# Tell Nim the paths to Nimble packages. We need this because we ran `nimble lock`.
+# The below lines are added by `nimble setup`.
+# begin Nimble config (version 2)
+--noNimblePath
+when withDir(thisDir(), system.fileExists("nimble.paths")):
+  include "nimble.paths"
+# end Nimble config

configlet.nimble

@@ -17,9 +17,11 @@ bin           = @["configlet"]
 
 # Dependencies
 requires "nim >= 2.0.0"
-requires "jsony#ea811bec7fa50f5abd3088ba94cda74285e93f18"       # 1.1.5  (2023-02-09)
-requires "parsetoml#6e5e16179fa2db60f2f37d8b1af4128aaa9c8aaf"   # 0.7.1  (2023-08-06)
-requires "supersnappy#e4df8cb5468dd96fc5a4764028e20c8a3942f16a" # 2.1.3  (2022-06-12)
+requires "jsony"
+requires "parsetoml"
+requires "supersnappy"
 
 task test, "Runs the test suite":
+  if not fileExists("nimble.paths"):
+    exec "nimble setup"
   exec "nim r ./tests/all_tests.nim"

nimble.lock

@@ -0,0 +1,36 @@
+{
+  "version": 2,
+  "packages": {
+    "supersnappy": {
+      "version": "2.1.3",
+      "vcsRevision": "e4df8cb5468dd96fc5a4764028e20c8a3942f16a",
+      "url": "https://github.com/guzba/supersnappy",
+      "downloadMethod": "git",
+      "dependencies": [],
+      "checksums": {
+        "sha1": "36a05ee6befe3764ed8e2a6fb5d0882c2fd090f8"
+      }
+    },
+    "jsony": {
+      "version": "1.1.5",
+      "vcsRevision": "ea811bec7fa50f5abd3088ba94cda74285e93f18",
+      "url": "https://github.com/treeform/jsony",
+      "downloadMethod": "git",
+      "dependencies": [],
+      "checksums": {
+        "sha1": "6aeb83e7481ca8686396a568096054bc668294df"
+      }
+    },
+    "parsetoml": {
+      "version": "0.7.1",
+      "vcsRevision": "6e5e16179fa2db60f2f37d8b1af4128aaa9c8aaf",
+      "url": "https://github.com/NimParsers/parsetoml.git",
+      "downloadMethod": "git",
+      "dependencies": [],
+      "checksums": {
+        "sha1": "586fe63467a674008c4445ed1b8ac882177d7103"
+      }
+    }
+  },
+  "tasks": {}
+}