chore: regenerate common templates (#203)

* chore(ci): fix typo in restrict presubmit samples ITs to only snapshot

Fixes below error in Java repos when googleapis/synthtool#804 was merged:
```
github/java-bigquerystorage/.kokoro/build.sh: line 81: pushd: {SAMPLES_DIR}: No such file or directory
```

Thanks @kolea2 for spotting this in Fusion build logs.

cc @chingor13

Source-Author: Stephanie Wang <[email protected]>
Source-Date: Mon Oct 26 13:44:04 2020 -0400
Source-Repo: googleapis/synthtool
Source-Sha: f68649c5f26bcff6817c6d21e90dac0fc71fef8e
Source-Link: googleapis/synthtool@f68649c

* chore(java): enable generated-files-bot

This bot will comment on pull requests that modify templated files. For java, we configure to read from our 2 synth.metadata files: (primary templates and README)

Source-Author: Jeff Ching <[email protected]>
Source-Date: Fri Oct 30 14:22:02 2020 -0700
Source-Repo: googleapis/synthtool
Source-Sha: b19b401571e77192f8dd38eab5fb2300a0de9324
Source-Link: googleapis/synthtool@b19b401

.github/generated-files-bot.yml

@@ -0,0 +1,7 @@
+externalManifests:
+- type: json
+  file: 'synth.metadata'
+  jsonpath: '$.generatedFiles[*]'
+- type: json
+  file: '.github/readme/synth.metadata/synth.metadata'
+  jsonpath: '$.generatedFiles[*]'

.kokoro/build.sh

@@ -78,7 +78,7 @@ samples)
 
     if [[ -f ${SAMPLES_DIR}/pom.xml ]]
     then
-        pushd {SAMPLES_DIR}
+        pushd ${SAMPLES_DIR}
         mvn -B \
           -Penable-samples \
           -DtrimStackTrace=false \

synth.metadata

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-shared-dependencies.git",
-        "sha": "71979b715609d28c83c7a2291a3bcaf7eee94131"
+        "sha": "2c1438355d733e2d446dac8ad5b58c319523787c"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "5f6ef0ec5501d33c4667885b37a7685a30d41a76"
+        "sha": "b19b401571e77192f8dd38eab5fb2300a0de9324"
       }
     }
   ],
@@ -21,6 +21,7 @@
     ".github/ISSUE_TEMPLATE/feature_request.md",
     ".github/ISSUE_TEMPLATE/support_request.md",
     ".github/PULL_REQUEST_TEMPLATE.md",
+    ".github/generated-files-bot.yml",
     ".github/readme/synth.py",
     ".github/snippet-bot.yml",
     ".github/trusted-contribution.yml",