[WIP]: new-plugin CI workflow

.github/workflows/new-plugin.yml

@@ -0,0 +1,96 @@
+name: new-plugin
+on:
+  push:
+    branch:
+      - "main"
+    paths:
+      - "plugins/**"
+
+jobs:
+  job1:
+    name: TODO name the job
+    runs-on: ubuntu-latest
+    timeout-minutes: 40
+    if: github.repository == 'nix-community/nixvim'
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          ssh-key: ${{ secrets.CI_UPDATE_SSH_KEY }}
+
+      - name: Install Nix
+        uses: cachix/install-nix-action@v26
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+          github_access_token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Get plugins info
+        run: |
+          OLD="$(
+            nix eval 'github:${{ github.repository }}/${{ github.event.before }}#nixvimConfiguration.options.plugins' \
+              --apply 'builtins.attrNames' \
+              --json
+          )"
+          NEW="$(
+            nix eval '.#nixvimConfiguration.options.plugins' \
+              --apply 'builtins.attrNames' \
+              --json
+          )"
+          # TODO: compare OLD and NEW
+
+      - name: Get PR info
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          if JSON="$(
+            gh api  \
+              -H "Accept: application/vnd.github+json" \
+              -H "X-GitHub-Api-Version: 2022-11-28" \
+              /repos/${{ github.repository }}/commits/${{ github.sha }}/pulls
+          )"
+          then
+            # TODO: use PR info
+          else
+            # TODO: handle error getting PR info
+          fi
+
+      - name: Send matrix message
+        uses: lkiesow/matrix-notification@v1
+        with:
+          # The Matrix home server to send the message to
+          # Default: matrix.org
+          server: matrix.org
+          # TODO: token
+          token: ...
+          room: "!oOLohuKTgwSAvIxmdO:matrix.org"
+          # The message to send (optional)
+          message: Hello world
+          # An HTML formatted version of the message to send
+          formatted_message: Hello <b>World</b>!
+          # Whether to install the `matrix-msg` exe
+          # Only needed if you wish to send messages in other steps
+          # We could use this to print a "summary" and a matrix message in the same step, for example
+          tool: false
+
+      - name: Print summary
+        run: |
+          # FIXME: copied from update workflow
+          # TODO: adapt to this workflow
+          num="${{ steps.pr.outputs.pull-request-number }}"
+          pr_url="${{ steps.pr.outputs.pull-request-url }}"
+          pr_branch="${{ steps.pr.outputs.pull-request-branch }}"
+          head="${{ steps.pr.outputs.pull-request-head-sha }}"
+          operation="${{ steps.pr.outputs.pull-request-operation }}"
+
+          # stdout
+          echo "${head:0:6} pushed to ${pr_branch}"
+          echo "${pr} was ${operation}."
+
+          # markdown summary
+          echo "## ${{ github.ref_name }}" >> $GITHUB_STEP_SUMMARY
+          echo >> $GITHUB_STEP_SUMMARY
+          echo "\`${head:0:6}\` pushed to \`${pr_branch}\`" >> $GITHUB_STEP_SUMMARY
+          echo >> $GITHUB_STEP_SUMMARY
+          echo "[#${num}](${pr_url}) was ${operation}." >> $GITHUB_STEP_SUMMARY
+          echo >> $GITHUB_STEP_SUMMARY