workflows: switch small jobs to ubuntu-slim

Save some resources.  In principle the setup jobs could switch too, but
find-container-digest uses skopeo which isn't installed in that image.

Signed-off-by: Benjamin Gilbert <bgilbert@cs.cmu.edu>

Author: bgilbert

.github/workflows/event-issue.yml

@@ -15,7 +15,7 @@ env:
 jobs:
   issue-event:
     name: Process
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     outputs:
       bot-user: ${{ steps.bot-user.outputs.username }}
     steps:

.github/workflows/event-pr.yml

@@ -16,7 +16,7 @@ env:
 jobs:
   pr-event:
     name: Process
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - name: Get bot username
         id: bot-user

.github/workflows/main.yml

@@ -13,7 +13,7 @@ permissions:
 jobs:
   pre-commit:
     name: Rerun pre-commit checks
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - name: Check out repo
         uses: actions/checkout@v5
@@ -30,6 +30,7 @@ jobs:
           key: pre-commit|${{ env.pythonLocation }}|${{ hashFiles('.pre-commit-config.yaml') }}
       - name: Run pre-commit hooks
         run: pre-commit run -a --show-diff-on-failure --color=always
+
   setup:
     name: Set up
     runs-on: ubuntu-latest

.github/workflows/pr.yml

@@ -12,7 +12,7 @@ permissions:
 jobs:
   pre-commit:
     name: Rerun pre-commit checks
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - name: Check out repo
         uses: actions/checkout@v5
@@ -29,6 +29,7 @@ jobs:
           key: pre-commit|${{ env.pythonLocation }}|${{ hashFiles('.pre-commit-config.yaml') }}
       - name: Run pre-commit hooks
         run: pre-commit run -a --show-diff-on-failure --color=always
+
   setup:
     name: Set up
     runs-on: ubuntu-latest

.github/workflows/update-check.yml

@@ -24,7 +24,7 @@ env:
 jobs:
   update:
     name: Update
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - name: Update Python
         uses: actions/setup-python@v6