chore: merge all lint workflows

Github unfortunately doesn't deal well with multiple workflows using a similar
name (in this case "lint"). It is currently required in order to do fine-grained
event triggers, since there's no need to run an action linter if the actions werern't changed.

We now instead look at what files have changed and skip running a job if it doesn't apply.

.github/workflows/lint.yml

@@ -0,0 +1,96 @@
+name: lint
+on:
+  pull_request:
+    paths:
+      # actionlint
+      - ".github/workflows/*.yml"
+      # prettier
+      - "**.md"
+      - "**.yml"
+      # shellcheck & shfmt
+      - "**.sh"
+
+jobs:
+  # This job fetches changed files that others will use to see if they should be run or not.
+  # If this file changes, any script should also fire.
+  changed:
+    runs-on: ubuntu-22.04
+    outputs:
+      files: ${{ steps.all.outputs.all_changed_files }}
+      self_changed: ${{ steps.lint.outputs.any_changed }}
+    steps:
+      - uses: actions/checkout@v3.0.2
+        with:
+          fetch-depth: 0
+      - name: Get a list of changed files
+        id: all
+        uses: tj-actions/changed-files@v29.0.9
+      - name: Check if this file is changed
+        id: lint
+        uses: tj-actions/changed-files@v29.0.9
+        with:
+          files: ".github/workflows/lint.yml"
+
+  actionlint:
+    name: actionlint
+    runs-on: ubuntu-22.04
+    needs: changed
+    if: ${{ contains(needs.changed.outputs.files, '.github/workflows') }}
+    steps:
+      - uses: actions/checkout@v3.0.2
+      - name: Install Actionlint
+        env:
+          ACTIONLINT_VERSION: 1.6.18
+        run: |
+          wget -q -O- "https://github.com/rhysd/actionlint/releases/download/v${ACTIONLINT_VERSION}/actionlint_${ACTIONLINT_VERSION}_linux_amd64.tar.gz" | tar -x -z -C . actionlint && \
+          mv actionlint /usr/local/bin
+      - name: Run Actionlint
+        run: |
+          actionlint -format '{{range $err := .}}::error file={{$err.Filepath}},line={{$err.Line}},col={{$err.Column}}::{{$err.Message}}{{end}}' -ignore 'SC2016:' .github/workflows/*.yml
+
+  prettier:
+    name: prettier
+    runs-on: ubuntu-22.04
+    needs: changed
+    if: ${{ contains(needs.changed.outputs.files, '.md') || contains(needs.changed.outputs.files, '.yml') || needs.changed.outputs.self_changed }}
+    steps:
+      - uses: actions/checkout@v3.0.2
+      - uses: actions/setup-node@v3.4.1
+        with:
+          node-version: 18
+      - name: install prettier
+        run: npm install -g prettier
+      - name: run prettier
+        run: prettier -c .
+  shellcheck:
+    name: shellcheck
+    runs-on: ubuntu-22.04
+    needs: changed
+    if: ${{ contains(needs.changed.outputs.files, '.sh') || needs.changed.outputs.self_changed }}
+    env:
+      SHELLCHECK_VERSION: 0.8.0
+    steps:
+      - uses: actions/checkout@v3.0.2
+      - name: install shellcheck
+        run: |
+          wget -q -O - "https://github.com/koalaman/shellcheck/releases/download/v${{ env.SHELLCHECK_VERSION }}/shellcheck-v${{ env.SHELLCHECK_VERSION }}.linux.x86_64.tar.xz" | tar -x -J --strip-components=1 -C . shellcheck-v${{ env.SHELLCHECK_VERSION }}/shellcheck && \
+          sudo mv shellcheck /usr/local/bin/
+      - name: verify shell scripts
+        # shellcheck source path is assumed to be the "root" git directory
+        run: shellcheck hadolint.sh lib/*.sh test/*.sh
+  shfmt:
+    name: shfmt
+    runs-on: ubuntu-22.04
+    needs: changed
+    if: ${{ contains(needs.changed.outputs.files, '.sh') || needs.changed.outputs.self_changed }}
+    env:
+      SHFMT_VERSION: 3.5.1
+    steps:
+      - uses: actions/checkout@v3.0.2
+      - name: install shfmt
+        run: |
+          wget -q -O shfmt "https://github.com/mvdan/sh/releases/download/v${{ env.SHFMT_VERSION }}/shfmt_v${{ env.SHFMT_VERSION }}_linux_amd64" && \
+          chmod +x shfmt && \
+          sudo mv shfmt /usr/local/bin/
+      - name: lint shell scripts
+        run: shfmt -i 2 -d hadolint.sh lib/*.sh test/*.sh