Pin dependencies (#2322)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/workflows/build_prepare.yaml

@@ -49,9 +49,9 @@ jobs:
         outputs:
             nightly-version: ${{ steps.versions.outputs.nightly }}
         steps:
-            - uses: actions/checkout@v4
+            - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
 
-            - uses: actions/setup-node@v4
+            - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
               with:
                   node-version-file: .node-version
                   cache: "yarn"
@@ -137,7 +137,7 @@ jobs:
                   echo "| Element Web | [$WEB_VERSION](https://github.com/element-hq/element-web/commit/$WEB_VERSION) |" >> $GITHUB_STEP_SUMMARY
                   echo "| JS SDK      | [$JS_VERSION](https://github.com/matrix-org/matrix-js-sdk/commit/$JS_VERSION) |" >> $GITHUB_STEP_SUMMARY
 
-            - uses: actions/upload-artifact@v4
+            - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
               with:
                   name: webapp
                   retention-days: 1