docker: bump golang from 1.20.5-alpine3.18 to 1.20.6-alpine3.18 (#374)

Bumps golang from 1.20.5-alpine3.18 to 1.20.6-alpine3.18.

---
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>

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.20.5-alpine3.18@sha256:fd9d9d7194ec40a9a6ae89fcaef3e47c47de7746dd5848ab5343695dbbd09f8c AS build
+FROM golang:1.20.6-alpine3.18@sha256:e9590019f04a00029bb5ac512c3d3dfff0ec0e66418cfb5035e22313af891d81 AS build
 
 COPY . /go/src/github.com/jauderho/bl3auto
 WORKDIR /go/src/github.com/jauderho/bl3auto