Update golang Docker tag to v1.21.5

Author: renovate[bot]

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.20.5 as build
+FROM golang:1.21.5 as build
 
 WORKDIR /work
 COPY . .
@@ -11,7 +11,7 @@ COPY --from=build /work/digicore_v3_backend /
 
 CMD ["/digicore_v3_backend"]
 
-FROM golang:1.20.5 as admin
+FROM golang:1.21.5 as admin
 
 WORKDIR "/app"
 RUN go install github.com/k0kubun/sqldef/cmd/[email protected]

Dockerfile.develop

@@ -1,4 +1,4 @@
-FROM golang:1.20.5 as development
+FROM golang:1.21.5 as development
 
 WORKDIR "/app"
 COPY go.mod go.sum ./
@@ -9,7 +9,7 @@ COPY . .
 
 CMD ["air", "-c", "./config/.air.toml"]
 
-FROM golang:1.20.5 as admin
+FROM golang:1.21.5 as admin
 
 WORKDIR "/app"
 RUN go install github.com/k0kubun/sqldef/cmd/[email protected]