ci: prevents action from running on forks (#11766)

.github/workflows/ci.yml

@@ -16,6 +16,7 @@ jobs:
     uses: ./.github/workflows/test.yml
 
   continuous-release:
+    if: github.repository == 'vuejs/core'
     runs-on: ubuntu-latest
     steps:
       - name: Checkout

.github/workflows/size-data.yml

@@ -18,6 +18,7 @@ env:
 
 jobs:
   upload:
+    if: github.repository == 'vuejs/core'
     runs-on: ubuntu-latest
 
     steps:

.github/workflows/size-report.yml

@@ -18,6 +18,7 @@ jobs:
   size-report:
     runs-on: ubuntu-latest
     if: >
+      github.repository == 'vuejs/core' &&
       github.event.workflow_run.event == 'pull_request' &&
       github.event.workflow_run.conclusion == 'success'
     steps: