fix(template tags): fixes issues with tags specified with uppercase (#2049)

* fix(template tags): fixes issues with tags specified with uppercase

* adds new validator for metadata tags

* fix(template tags): change tags to be lowercase

* fix(template tags docs): update docs to include lowercased tags

* fix(validator): change back to using isValidDnsLabel for tags

* fix(software catalog docs): use lowercase tags in docs

plugins/scaffolder-backend/sample-templates/create-react-app/template.yaml

@@ -5,9 +5,9 @@ metadata:
   title: Create React App Template
   description: Create a new CRA website project
   tags:
-    - Experimental
-    - React
-    - CRA
+    - experimental
+    - react
+    - cra
 spec:
   owner: web@example.com
   templater: cra

plugins/scaffolder-backend/sample-templates/react-ssr-template/template.yaml

@@ -5,8 +5,8 @@ metadata:
   title: React SSR Template
   description: Create a website powered with Next.js
   tags:
-    - Recommended
-    - React
+    - recommended
+    - react
 spec:
   owner: web@example.com
   templater: cookiecutter

plugins/scaffolder-backend/sample-templates/springboot-grpc-template/template.yaml

@@ -5,8 +5,8 @@ metadata:
   title: Spring Boot GRPC Service
   description: Create a simple microservice using gRPC and Spring Boot Java
   tags:
-    - Recommended
-    - Java
+    - recommended
+    - java
 spec:
   owner: service@example.com
   templater: cookiecutter