build(deps): Bump golang in /cmd/fluent-manager

Bumps golang from 1.20.2-alpine3.17 to 1.20.3-alpine3.17.

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

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

cmd/fluent-manager/Dockerfile

@@ -1,5 +1,5 @@
 # Build the manager binary
-FROM --platform=$BUILDPLATFORM golang:1.20.2-alpine3.17 as builder
+FROM --platform=$BUILDPLATFORM golang:1.20.3-alpine3.17 as builder
 
 WORKDIR /workspace
 # Copy the Go Modules manifests