build(deps): bump alpine from 3.12.2 to 3.12.3

Bumps alpine from 3.12.2 to 3.12.3.

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

Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.12.2
+FROM alpine:3.12.3
 
 ARG GETTEXT_PACKAGE_VERSION=0.20.2-r0
 ARG TOR_PACKAGE_VERSION=0.4.3.7-r0