[0.8] pin machulav/ec2-github-runner version - bm flow (#899)

backport #897 to 0.8

Author: meiravgri

.github/workflows/benchmark.yml

@@ -48,7 +48,7 @@ jobs:
           aws-region: ${{ secrets.AWS_REGION }}
       - name: Start EC2 runner
         id: start-ec2-runner
-        uses: machulav/ec2-github-runner@v2
+        uses: machulav/ec2-github-runner@v2.4.2
         with:
           mode: start
           github-token: ${{ secrets.GH_PERSONAL_ACCESS_TOKEN }}
@@ -128,7 +128,7 @@ jobs:
           aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
           aws-region: ${{ secrets.AWS_REGION }}
       - name: Stop EC2 runner
-        uses: machulav/ec2-github-runner@v2
+        uses: machulav/ec2-github-runner@v2.4.2
         with:
           mode: stop
           github-token: ${{ secrets.GH_PERSONAL_ACCESS_TOKEN }}