Bloat check scheduling: update timing to 5 minutes, checkout code sin…

…ce scripts are in the code (project-chip#1556)

* Run the bloat check script as a scheduled github workflow.

Should generate bloat reports on any pull requests.

* Bloat script requires checkout. Also updated latest build image

* Run bloat check more frequently

.github/workflows/bloat_check.yaml

@@ -1,7 +1,7 @@
 name: Bloat Check
 on:
     schedule:
-        - cron: '*/10 * * * *'
+        - cron: '*/5 * * * *'
 
 
 jobs:
@@ -11,9 +11,12 @@ jobs:
         runs-on: ubuntu-latest
 
         container:
-            image: "connectedhomeip/chip-build-openssl:0.2.18"
+            image: connectedhomeip/chip-build:0.3.0
 
         steps:
+            - name: Checkout
+              uses: actions/checkout@v2
+
             - name: Report
               run: |
                   scripts/helpers/bloat_check.py                        \