Add option to ignore prerelease on update (#96)

lib/Inputs.js

@@ -105,10 +105,18 @@ class CoreInputs {
         }
         return this.context.repo.owner;
     }
-    get prerelease() {
+    get createdPrerelease() {
         const preRelease = core.getInput('prerelease');
         return preRelease == 'true';
     }
+    static get omitPrereleaseDuringUpdate() {
+        return core.getInput('omitPrereleaseDuringUpdate') == 'true';
+    }
+    get updatedPrerelease() {
+        if (CoreInputs.omitPrereleaseDuringUpdate)
+            return undefined;
+        return this.createdPrerelease;
+    }
     get replacesArtifacts() {
         const replaces = core.getInput('replacesArtifacts');
         return replaces == 'true';