Adapt CPU resource request and limit

After the new pod wasn't able to be scheduled due to insufficient CPU
resources, I checked the current usage and it was well below the
requested amount. Lowering request and limit fixed the deployment issue.

kubernetes/gitea-server.yaml

@@ -42,10 +42,10 @@ spec:
           name: gitea-server-data
         resources:
           requests:
-            cpu: 250m
+            cpu: 150m
             memory: 256Mi
           limits:
-            cpu: 500m
+            cpu: 250m
             memory: 512Mi
       restartPolicy: Always
       volumes: