Adjust GitHub action timeouts

Author: seratch

.github/workflows/unit-tests-jdk-14.yml

@@ -8,7 +8,7 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
-    timeout-minutes: 15
+    timeout-minutes: 12
     strategy:
       matrix:
         java-version: ['14']

.github/workflows/unit-tests-jdk-8.yml

@@ -8,7 +8,7 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
-    timeout-minutes: 15
+    timeout-minutes: 12
     strategy:
       matrix:
         java-version: ['8']