chore: catch up label updates (#3951)

Signed-off-by: tison <wander4096@gmail.com>

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -1,7 +1,7 @@
 ---
 name: Bug report
 description: Is something not working? Help us fix it!
-labels: [ "bug" ]
+labels: [ "C-bug" ]
 body:
   - type: markdown
     attributes:

.github/ISSUE_TEMPLATE/config.yml

@@ -4,5 +4,5 @@ contact_links:
     url: https://greptime.com/slack
     about: Get free help from the Greptime community
   - name: Greptime Community Discussion
-    url: https://github.com/greptimeTeam/greptimedb/discussions
+    url: https://github.com/greptimeTeam/discussions
     about: Get free help from the Greptime community

.github/ISSUE_TEMPLATE/enhancement.yml

@@ -1,7 +1,7 @@
 ---
 name: Enhancement
 description: Suggest an enhancement to existing functionality
-labels: [ "enhancement" ]
+labels: [ "C-enhancement" ]
 body:
   - type: dropdown
     id: type

.github/ISSUE_TEMPLATE/feature.yml

@@ -1,7 +1,7 @@
 ---
-name: Feature request
+name: New Feature
 description: Suggest a new feature for GreptimeDB
-labels: [ "feature request" ]
+labels: [ "C-feature" ]
 body:
   - type: markdown
     id: info