chore(ci): update branch names in workflow triggers (#374)

- Changed branch name from 'v2.x' to '2.x' in analysis workflow
- Changed branch name from 'v2.x' to '2.x' in lint workflow
- Changed branch name from 'v2.x' to '2.x' in test workflow

Author: flc1125

.github/workflows/analysis.yml

@@ -3,10 +3,10 @@ name: Go Static Analysis
 on:
   push:
     branches:
-      - v2.x
+      - 2.x
   pull_request:
     branches:
-      - v2.x
+      - 2.x
 
 jobs:
   golangci:

.github/workflows/lint.yml

@@ -3,10 +3,10 @@ name: Go Lint
 on:
   push:
     branches:
-      - v2.x
+      - 2.x
   pull_request:
     branches:
-      - v2.x
+      - 2.x
 
 jobs:
   golangci:

.github/workflows/test.yml

@@ -2,10 +2,10 @@ name: Go Test
 on:
   push:
     branches:
-      - v2.x
+      - 2.x
   pull_request:
     branches:
-      - v2.x
+      - 2.x
 env:
   GOPROXY: "https://proxy.golang.org"