Bump the docker-ingester group across 1 directory with 2 updates

Bumps the docker-ingester group with 2 updates in the /cmd/ingester directory: golang and alpine.


Updates `golang` from 1.20.2-alpine3.17 to 1.21.5-alpine3.17

Updates `alpine` from 3.19.1 to 3.20.3

---
updated-dependencies:
- dependency-name: golang
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: docker-ingester
- dependency-name: alpine
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: docker-ingester
...

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

cmd/ingester/Dockerfile

@@ -1,13 +1,13 @@
 # We can't go past 1.20.2 until this issue is solved: https://github.com/golang/go/issues/62130#issuecomment-1687335898
-FROM golang:1.20.2-alpine3.17 as build
+FROM golang:1.21.5-alpine3.17 as build
 RUN apk update && apk add git make
 WORKDIR /ingester
 COPY go.mod go.sum ./
 RUN go mod download
 COPY . .
 RUN make build-ingester
 
-FROM alpine:3.19.1
+FROM alpine:3.20.3
 RUN apk update && apk add --no-cache ca-certificates
 RUN mkdir /ingester
 COPY --from=build /ingester/ingester /ingester