[openwrt/openwrt] CI: build: limit cache save/delete only on push events

[LEDE Commits]

ansuel pushed a commit to openwrt/openwrt.git, branch openwrt-23.05:
https://git.openwrt.org/5bfa66bcf3bfcadea059bae1f1d18b388318caa4

commit 5bfa66bcf3bfcadea059bae1f1d18b388318caa4
Author: Christian Marangi <ansuelsmth at gmail.com>
AuthorDate: Sun May 28 09:11:29 2023 +0200

    CI: build: limit cache save/delete only on push events
    
    Limit ccache cache save/delete only on push events. Saving ccache
    cache for pull request will result in bloat and refreshing ccache is not
    possible due to security measure on enforcing read permission on
    pull_request events.
    
    Signed-off-by: Christian Marangi <ansuelsmth at gmail.com>
    (cherry picked from commit ff66a7c1c0f012324c0d2d90f047e6976c4fba11)
---
 .github/workflows/build.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 0c0c05f402..95d19f4c4e 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -498,7 +498,7 @@ jobs:
           path: "openwrt/logs"
 
       - name: Delete already present ccache cache
-        if: steps.restore-ccache-cache.outputs.cache-hit == 'true' && inputs.use_ccache_cache == true
+        if: steps.restore-ccache-cache.outputs.cache-hit == 'true' && inputs.use_ccache_cache == true  && github.event_name == 'push'
         uses: octokit/request-action at v2.x
         with:
           route: DELETE /repos/{repository}/actions/caches?key={key}
@@ -508,7 +508,7 @@ jobs:
           INPUT_KEY: ${{ steps.restore-ccache-cache.outputs.cache-primary-key }}
 
       - name: Save ccache cache
-        if: inputs.use_ccache_cache == true
+        if: inputs.use_ccache_cache == true && github.event_name == 'push'
         uses: actions/cache/save at v3
         with:
           path: openwrt/.ccache