Bump golang from 1.21.3 to 1.21.4 (#524)

Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM golang:1.21.3@sha256:b113af1e8b06f06a18ad41a6b331646dff587d7a4cf740f4852d16c49ed8ad73 AS builder
+FROM golang:1.21.4@sha256:81cd210ae58a6529d832af2892db822b30d84f817a671b8e1c15cff0b271a3db AS builder
 ENV APP_ROOT=/opt/app-root
 ENV GOPATH=$APP_ROOT
 
@@ -29,7 +29,7 @@ RUN go build -ldflags "${SERVER_LDFLAGS}" ./cmd/timestamp-server
 RUN CGO_ENABLED=0 go build -gcflags "all=-N -l" -ldflags "${SERVER_LDFLAGS}" -o timestamp-server_debug ./cmd/timestamp-server
 
 # Multi-Stage production build
-FROM golang:1.21.3@sha256:b113af1e8b06f06a18ad41a6b331646dff587d7a4cf740f4852d16c49ed8ad73 as deploy
+FROM golang:1.21.4@sha256:81cd210ae58a6529d832af2892db822b30d84f817a671b8e1c15cff0b271a3db as deploy
 
 # Retrieve the binary from the previous stage
 COPY --from=builder /opt/app-root/src/timestamp-server /usr/local/bin/timestamp-server