Bump golang from 8f9a1ec to 20f9ab5 in /internal/witness/cmd/feed…

…er (#1201)

Bumps golang from `8f9a1ec` to `20f9ab5`.

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

internal/witness/cmd/feeder/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.21.3-bookworm@sha256:8f9a1ec71422440343f9a27ec694ce65196ff95bd60f1e79a53b65eb37f1930c as builder
+FROM golang:1.21.3-bookworm@sha256:20f9ab52a8c3598ef13f86c9bc3b94db400e13df115ecacd8c3dfd0c0f060208 as builder
 
 ARG GOFLAGS=""
 ENV GOFLAGS=$GOFLAGS