release: Refactor release tracks for Linux packages and Docker

Support 4 release tracks instead of 2:
- sing-box / latest (stable release)
- sing-box-beta / latest-beta (stable pre-release)
- sing-box-testing / latest-testing (testing branch)
- sing-box-oldstable / latest-oldstable (oldstable branch)

Track is detected via git branch --contains and git tag,
replacing the old version-string hyphen check.

.github/workflows/linux.yml

@@ -7,11 +7,6 @@ on:
         description: "Version name"
         required: true
         type: string
-      forceBeta:
-        description: "Force beta"
-        required: false
-        type: boolean
-        default: false
   release:
     types:
       - published
@@ -103,14 +98,8 @@ jobs:
       - name: Set mtime
         run: |-
           TZ=UTC touch -t '197001010000' dist/sing-box
-      - name: Set name
-        if: (! contains(needs.calculate_version.outputs.version, '-')) && !inputs.forceBeta
-        run: |-
-          echo "NAME=sing-box" >> "$GITHUB_ENV"
-      - name: Set beta name
-        if: contains(needs.calculate_version.outputs.version, '-') || inputs.forceBeta
-        run: |-
-          echo "NAME=sing-box-beta" >> "$GITHUB_ENV"
+      - name: Detect track
+        run: bash .github/detect_track.sh
       - name: Set version
         run: |-
           PKG_VERSION="${{ needs.calculate_version.outputs.version }}"