Use team mention for github stale actions (matomo-org#17705)

Author: sgiehl

.github/workflows/follow-up-reviews.yml

@@ -16,5 +16,5 @@ jobs:
           only-pr-labels: Needs Review
           days-before-issue-stale: -1
           days-before-issue-close: -1
-          stale-pr-message: This issue is in "needs review" but there has been no activity for 7 days. ping @tsteur @justinvelluppillai @sgiehl @diosmosis
+          stale-pr-message: This issue is in "needs review" but there has been no activity for 7 days. ping @matomo-org/core-reviewers
           stale-pr-label: Stale

.github/workflows/inactive-prs-closing-message.yaml

@@ -16,5 +16,5 @@ jobs:
           days-before-issue-stale: -1
           days-before-issue-close: -1
           exempt-pr-labels: Do not close
-          stale-pr-message: This PR was last updated more than one month ago, maybe it's time to close it. Please check if there is anything we still can do or close this PR. ping @tsteur @justinvelluppillai @sgiehl @diosmosis
+          stale-pr-message: This PR was last updated more than one month ago, maybe it's time to close it. Please check if there is anything we still can do or close this PR. ping @matomo-org/core-reviewers
           stale-pr-label: Stale for long