chore: pin action to v3 and remove concurrency from moon

v3 was the action version of the previous base job.
We want to do changes one by one, and v4 (current main) does not work
without the concurrency change. This just brings the concurrency change
that we will need to set the action version to the latest (v4) again.

Author: GuillaumeLagrange

.github/workflows/codspeed.yml

@@ -25,7 +25,7 @@ jobs:
 
       - name: Run benchmarks
         # use version from `main` branch to always test the latest version, in real projects, use a tag, like `@v2`
-        uses: CodSpeedHQ/action@main
+        uses: CodSpeedHQ/action@v3
         with:
           mode: instrumentation
           run: |
@@ -52,7 +52,7 @@ jobs:
 
       - name: Run benchmarks
         # use version from `main` branch to always test the latest version, in real projects, use a tag, like `@v2`
-        uses: CodSpeedHQ/action@main
+        uses: CodSpeedHQ/action@v3
         with:
           mode: walltime
           run: |