build: Run size-limit action on master (#5314)

We need to run size-limit on master so that we upload size assets that we can do comparisons with.

Author: AbhiPrasad

.github/workflows/build.yml

@@ -178,7 +178,7 @@ jobs:
     timeout-minutes: 15
     runs-on: ubuntu-latest
     # Size Check will error out outside of the context of a PR
-    if: ${{ github.event_name == 'pull_request' }}
+    if: ${{ github.event_name == 'pull_request' }} || ${{ startsWith(github.ref, 'refs/heads/master/') }}
     steps:
       - name: Check out current commit (${{ needs.job_get_metadata.outputs.commit_label }})
         uses: actions/checkout@v2