[CI] Add weights verification jobs (#6996)

* add weights verification job

* switch to a github action

* rename script..

* add swc check

* fix perms...

* debugging

* fix comments, remove artifact. I hate CI

* switch to swc compare files

* sigh

* switch back to compare commits

* fix output

* fix output... again. yay markdown!

* remove test version number

* remove TODO

* switch to docker image

* Revert "remove TODO"

This reverts commit c313afd4604c437ebd25ffa84bb8cc7d95cd1092.

* fix docker registry url

* revert docker experiment

too janky. will fix upstream stuff and fix as a separate PR

reverts commits:

- 3be2043a95f15579453e68ff96360f60aeae24e3
- fd17a0fbf8a75449720fe3861f941f4a91fcc9c7
- 59f0ebfef49e37060cb2dc63cf67c7809befcf57

---------

Co-authored-by: parity-processbot <>
Co-authored-by: Martin <parity@tofu.lan>

polkadot/.github/workflows/check-weights.yml

@@ -0,0 +1,49 @@
+name: Check updated weights
+
+on:
+  pull_request:
+    paths:
+      - 'runtime/*/src/weights/**'
+
+jobs:
+  check_weights_files:
+    strategy:
+      fail-fast: false
+      matrix:
+        runtime: [westend, kusama, polkadot, rococo]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v3
+      - name: Check weights files
+        shell: bash
+        run: |
+          scripts/ci/github/verify_updated_weights.sh ${{ matrix.runtime }}
+
+  # This job uses https://github.com/ggwpez/substrate-weight-compare to compare the weights of the current
+  # release with the last release, then adds them as a comment to the PR.
+  check_weight_changes:
+    strategy:
+      fail-fast: false
+      matrix:
+        runtime: [westend, kusama, polkadot, rococo]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Get latest release
+        run: |
+          LAST_RELEASE=$(curl -s https://api.github.com/repos/paritytech/polkadot/releases/latest | jq -r .tag_name)
+          echo "LAST_RELEASE=$LAST_RELEASE" >> $GITHUB_ENV
+      - name: Checkout current sources
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - name: Check weight changes
+        shell: bash
+        run: |
+          cargo install --git https://github.com/ggwpez/substrate-weight-compare swc
+          ./scripts/ci/github/check_weights_swc.sh ${{ matrix.runtime }} "$LAST_RELEASE" | tee swc_output_${{ matrix.runtime }}.md
+      - name: Add comment
+        uses: thollander/actions-comment-pull-request@v2
+        with:
+          filePath: ./swc_output_${{ matrix.runtime }}.md
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}