chore(deps): bump alpine in /aries/agents/aath-backchannel

Bumps alpine from 3.15.4 to 3.20.0.

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

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

aries/agents/aath-backchannel/Dockerfile.aries-vcx

@@ -1,4 +1,4 @@
-FROM alpine:3.15.4 AS builder
+FROM alpine:3.20.0 AS builder
 
 ARG UID=1000
 ARG GID=1000
@@ -27,7 +27,7 @@ WORKDIR ./aries-vcx-backchannel
 COPY --chown=indy:indy ./aries-vcx/Cargo.lock ./aries-vcx/Cargo.toml ./
 RUN cargo build
 
-FROM alpine:3.15.4
+FROM alpine:3.20.0
 
 ARG UID=1000
 ARG GID=1000