improved PR workflow

.github/actions/get-semver-label-from-pr/action.yml

@@ -0,0 +1,34 @@
+# used to extract the version from a semver label
+name: get-semver-label-from-pr
+description: Gets semver label from PR event
+outputs:
+  semver-label:
+    description: Semver label name
+    value: ${{ steps.get-label.outputs.result }}
+  semver-bump:
+    description: Semver bump type
+    value: ${{ steps.get-bump.outputs.result }}
+runs:
+  using: 'composite'
+  steps:
+    - uses: actions/github-script@v6
+      id: get-label
+      with:
+        script: |
+          const labels = context.payload.pull_request.labels
+          const semverLabels = labels.filter(label => label.name.startsWith('semver:'))
+          if (semverLabels.length === 0) {
+            return core.setFailed('No semver label found')
+          }
+          if (semverLabels.length > 1) {
+            return core.setFailed('Cannot have multiple semver labels')
+          }
+          return semverLabels[0].name
+    - uses: actions/github-script@v6
+      id: get-bump
+      if: ${{ success() }}
+      env:
+        LABEL_NAME: ${{ steps.get-label.outputs.result }}
+      with:
+        script: |
+          return process.env.LABEL_NAME.replace('semver: ', '')

.github/workflows/pr-has-semver-label.yml

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+name: pr-has-semver-label
+on:
+  pull_request_target:
+    branches:
+      - main
+    types:
+      - opened
+      - labeled
+      - unlabeled
+      - ready_for_review
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+jobs:
+  pr-has-semver-label:
+    if: github.event.pull_request.draft == false
+    name: pr-has-semver-label
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+          sparse-checkout: |
+            .github
+      - name: Does the PR have a single semver label?
+        id: get-semver-label
+        uses: ./.github/actions/get-semver-label-from-pr
+      - name: update GitHub Action summary
+        id: set-semver-label-output
+        if: ${{ success() }}
+        run: echo "PR merge will cause a ${{ steps.get-semver-label.outputs.semver-bump }} version bump" >> $GITHUB_STEP_SUMMARY