cut releases on CI, when the version number in version.json is changed

.github/workflows/release-check.yml

@@ -0,0 +1,45 @@
+name: Release Checker
+on:
+  pull_request:
+    paths: [ 'version.json' ]
+    branches: [ master ]
+
+jobs:
+  releaser:
+    runs-on: ubuntu-latest
+    env:
+      HIGHESTRELEASED: ""
+      VERSION: ""
+      GORELEASE: ""
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-go@v2
+        with:
+          go-version: "1.16.x"
+      - name: Install gorelease
+        run: go install golang.org/x/exp/cmd/[email protected]
+      - name: Determine version
+        run: echo "VERSION=$(jq -r .version version.json)" >> $GITHUB_ENV
+      - name: Determine highest released version
+        run: echo "HIGHESTRELEASED=$(go list -m -versions | tr " " "\n" | tail -n 1)" >> $GITHUB_ENV
+      - name: Run gorelease
+        id: gorelease
+        if: env.VERSION != env.HIGHESTRELEASED
+        run: |
+          output=$(gorelease || true)
+          # dealing with multi-line strings in GitHub Actions is a pain
+          echo "GORELEASE<<EOF" >> $GITHUB_ENV
+          echo "$output" >> $GITHUB_ENV
+          echo "EOF" >> $GITHUB_ENV
+      - uses: marocchino/sticky-pull-request-comment@v2
+        if: env.VERSION != env.HIGHESTRELEASED
+        with:
+          header: test
+          recreate: true
+          message: |
+            Most recent release is: ${{ env.HIGHESTRELEASED }}
+
+            `gorelease` says:
+            ```
+            ${{ env.GORELEASE }}
+            ```

.github/workflows/releaser.yml

@@ -0,0 +1,19 @@
+name: Releaser
+on:
+  push:
+    paths: [ 'version.json' ]
+    branches: [ master ]
+
+jobs:
+  releaser:
+    runs-on: ubuntu-latest
+    env:
+      VERSION: ""
+    steps:
+      - uses: actions/checkout@v2
+      - name: Determine version
+        run: echo "VERSION=$(jq -r .version version.json)" >> $GITHUB_ENV
+      - name: Create release
+        run: |
+          git tag ${{ env.VERSION }}
+          git push --tags

version.json

@@ -0,0 +1,3 @@
+{
+  "version": "v0.11.2"
+}