Add an MSRV check to the CI

closes tafia#479

.github/workflows/rust.yml

@@ -10,6 +10,13 @@ jobs:
     - name: Check fmt
       run: cargo fmt -- --check
 
+  msrv:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - uses: dtolnay/[email protected]
+    - run: cargo check --all-features
+
   test:
     strategy:
       matrix:

Cargo.toml

@@ -10,13 +10,14 @@ repository = "https://github.com/tafia/quick-xml"
 keywords = ["xml", "serde", "parser", "writer", "html"]
 categories = ["asynchronous", "encoding", "parsing", "parser-implementations"]
 license = "MIT"
+rust_version = "1.54"
 
 [dependencies]
 document-features = { version = "0.2", optional = true }
 encoding_rs = { version = "0.8", optional = true }
-serde = { version = "1.0", optional = true }
-tokio = { version = "1.21", optional = true, default-features = false, features = ["io-util"] }
-memchr = "2.5"
+serde = { version = "^1.0.100", optional = true }
+tokio = { version = "^1.0", optional = true, default-features = false, features = ["io-util"] }
+memchr = "^2.0"
 
 [dev-dependencies]
 criterion = "0.4"