Increase the timeout for e2e tests

This will increase the timeout for e2e tests as currently
the nightly e2e is getting failed with error
as `panic: test timed out after 20m0s`
This may be because of new tests getting added

Author: piyush-garg

Makefile

@@ -7,7 +7,7 @@ LDFLAGS=
 OUTPUT_DIR=bin
 GO           = go
 TIMEOUT_UNIT = 20m
-TIMEOUT_E2E  = 20m
+TIMEOUT_E2E  = 30m
 GO_TEST_FLAGS +=
 SHELL := bash