GHA: use ubuntu-slim in small jobs (#429)

Author: vszakats

.github/workflows/checksrc.yml

@@ -21,7 +21,7 @@ permissions: {}
 jobs:
   checksrc:
     name: 'checksrc'
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
         with:
@@ -32,7 +32,7 @@ jobs:
 
   dist:
     name: 'dist'
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
         with: