Add "Update parsers workflow"

.github/workflows/update-parsers-pr.yml

@@ -0,0 +1,28 @@
+name: Make Parser Update PR
+
+on: push
+
+jobs:
+  update-parsers:
+    name: Update parsers
+    runs-on: ubuntu-latest
+    #if: github.ref == 'master'
+    steps:
+      - uses: actions/checkout@v1
+
+      - name: Prepare
+        run: |
+          sudo apt-get update
+          sudo add-apt-repository universe
+          wget https://github.com/neovim/neovim/releases/download/nightly/nvim.appimage
+          chmod u+x nvim.appimage
+          mkdir -p ~/.local/share/nvim/site/pack/nvim-treesitter/start
+          ln -s $(pwd) ~/.local/share/nvim/site/pack/nvim-treesitter/start
+
+      # inspired by nvim-lspconfigs
+      - name: Update parsers
+        run: |
+          ./nvim.appimage --headless -c "luafile ./scripts/write-lockfile.lua" -c "q"
+
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v3