build(deps): bump alpine from 3.15.1 to 3.15.2

Bumps alpine from 3.15.1 to 3.15.2.

---
updated-dependencies:
- dependency-name: alpine
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Dockerfile

@@ -1,5 +1,5 @@
 # https://pkgs.alpinelinux.org/packages?name=obfs4proxy&arch=x86_64
-FROM docker.io/alpine:3.15.1
+FROM docker.io/alpine:3.15.2
 
 ARG TOR_PACKAGE_VERSION=0.4.6.9-r0
 ARG OBFS4PROXY_PACKAGE_VERSION=0.0.11-r5