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

docs/features/software-catalog/descriptor-format.md

@@ -370,8 +370,8 @@ metadata:
   description:
     Next.js application skeleton for creating isomorphic web applications.
   tags:
-    - Recommended
-    - React
+    - recommended
+    - react
 spec:
   owner: web@example.com
   templater: cookiecutter

docs/features/software-templates/adding-templates.md

@@ -22,8 +22,8 @@ metadata:
     Next.js application skeleton for creating isomorphic web applications.
   # some tags to display in the frontend
   tags:
-    - Recommended
-    - React
+    - recommended
+    - react
 spec:
   # which templater key to use in the templaters builder
   templater: cookiecutter

docs/features/software-templates/extending/create-your-own-templater.md

@@ -116,8 +116,8 @@ metadata:
   description:
     Next.js application skeleton for creating isomorphic web applications.
   tags:
-    - Recommended
-    - React
+    - recommended
+    - react
 spec:
   owner: web@example.com
   templater: handlebars