Drop prerelease flag in go releaser (#368)

* added knative 1.x tags format support to release workflow yaml

* removing go releaser pre release flag

* removed comment regarding pre release option after completing the release

.goreleaser.yml

@@ -40,5 +40,5 @@ changelog:
     - '^test:'
 release:
   draft: false
-  prerelease: true
+  prerelease: false
   name_template: "Release {{ .Tag }}"

RELEASE.md

@@ -65,7 +65,6 @@ git push origin knative-v1.0.0
 
 **Notes:**
 - To trigger the release workflow you cannot push more than 2 tags at a time.
-- After this process finishes, go to the [Release Section](https://github.com/vmware-tanzu/sources-for-knative/releases), edit the latest release and deselect the `this is a pre-release` option.
 
 ## Release Notes