set go function executable when download to local (apache#4743)

### Motivation

Currently golang function needs to be compiled before deploy to pulsar, so the executable permission is required when function package is downloaded to local node from bookkeeper. This PR is intent to make golang function package executable after download from bookkeeper, to make sure the function is ok to run.

pulsar-functions/worker/src/main/java/org/apache/pulsar/functions/worker/FunctionActioner.java

@@ -242,6 +242,11 @@ private void downloadFile(File pkgFile, boolean isPkgUrlProvided, FunctionMetaDa
         } finally {
             tempPkgFile.delete();
         }
+
+        if(details.getRuntime() == Function.FunctionDetails.Runtime.GO && !pkgFile.canExecute()) {
+            pkgFile.setExecutable(true);
+            log.info("Golang function package file {} is set to executable", pkgFile);
+        }
     }
 
     private void cleanupFunctionFiles(FunctionRuntimeInfo functionRuntimeInfo) {