Prepare 4.0.1 release

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh, ./bin/openapi3/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\. If contributing template-only or documentation-only changes which will change sample output, be sure to build the project first.
• Filed the PR against the correct branch: master, 4.1.x, 5.0.x. Default: master.
• Copied the technical committee to review the pull request if your PR is targeting a particular programming language.

Description of the PR

(details of the change, additional tests that have been done, reference to the issue for tracking, etc)

modules/openapi-generator/pom.xml

@@ -3,7 +3,7 @@
     <parent>
         <groupId>org.openapitools</groupId>
         <artifactId>openapi-generator-project</artifactId>
-        <version>4.0.1-SNAPSHOT</version>
+        <version>4.0.1</version>
         <relativePath>../..</relativePath>
     </parent>
     <modelVersion>4.0.0</modelVersion>
@@ -313,7 +313,7 @@
         <dependency>
             <groupId>org.openapitools</groupId>
             <artifactId>openapi-generator-core</artifactId>
-            <version>4.0.1-SNAPSHOT</version>
+            <version>4.0.1</version>
         </dependency>
     </dependencies>
     <repositories>

modules/openapi-generator-cli/pom.xml

@@ -3,7 +3,7 @@
     <parent>
         <groupId>org.openapitools</groupId>
         <artifactId>openapi-generator-project</artifactId>
-        <version>4.0.1-SNAPSHOT</version>
+        <version>4.0.1</version>
         <relativePath>../..</relativePath>
     </parent>
     <modelVersion>4.0.0</modelVersion>

modules/openapi-generator-core/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <artifactId>openapi-generator-project</artifactId>
     <groupId>org.openapitools</groupId>
-    <version>4.0.1-SNAPSHOT</version>
+    <version>4.0.1</version>
     <relativePath>../..</relativePath>
   </parent>
   <modelVersion>4.0.0</modelVersion>

modules/openapi-generator-gradle-plugin/samples/local-spec/README.md

@@ -17,5 +17,5 @@ gradle generateGoWithInvalidSpec
 The samples can be tested against other versions of the plugin using the `openApiGeneratorVersion` property. For example:
 
 ```bash
-gradle -PopenApiGeneratorVersion=4.0.0 openApiValidate
+gradle -PopenApiGeneratorVersion=4.0.1 openApiValidate
 ```

modules/openapi-generator-gradle-plugin/samples/local-spec/gradle.properties

-openApiGeneratorVersion=4.0.0
+openApiGeneratorVersion=4.0.1