keepalive: set committer information globally

A subsequent commit will add a step that wants to create merge commits
under certain circumstances, in which instance that information is
needed not only in the step that that creates a new commit but also the
one that performs a merge.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

.github/workflows/keepalive.yml

@@ -5,6 +5,9 @@ on:
     - cron: "23 19 17 * *" # 7:23pm on every 17th of the month
   workflow_dispatch:
 
+env:
+  GIT_CONFIG_PARAMETERS: "'user.name=CI' 'user.email=ci@github'"
+
 jobs:
   job:
     runs-on: ubuntu-latest
@@ -15,8 +18,6 @@ jobs:
         with:
           persist-credentials: 'true'
       - name: Create and push a commit
-        env:
-          GIT_CONFIG_PARAMETERS: "'user.name=CI' 'user.email=ci@github'"
         run: |
           mkdir -p .github/cached
           file='.github/cached/keepalive.txt'