fix(ci): changed the way of setting mirrors of apk

.github/workflows/ci.yml

@@ -19,7 +19,9 @@ jobs:
           ALPINE_MIRROR: ${{ secrets.ALPINE_MIRROR }}
         run: |
           set -e
-          echo "$ALPINE_MIRROR" > /etc/apk/repositories
+          ALPINE_VERSION=$(cat /etc/alpine-release | cut -d'.' -f1-2) && \
+          echo "${ALPINE_MIRROR}v${ALPINE_VERSION}/main" > /etc/apk/repositories && \
+          echo "${ALPINE_MIRROR}v${ALPINE_VERSION}/community" >> /etc/apk/repositories
           apk update
           apk add --no-cache git