Bump golang from 1.18.3 to 1.18.4 (#919)

Dockerfile

@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM golang:1.18.3@sha256:a452d6273ad03a47c2f29b898d6bb57630e77baf839651ef77d03e4e049c5bf3 AS builder
+FROM golang:1.18.4@sha256:9349ed889adb906efa5ebc06485fe1b6a12fb265a01c9266a137bb1352565560 AS builder
 ENV APP_ROOT=/opt/app-root
 ENV GOPATH=$APP_ROOT
 
@@ -30,7 +30,7 @@ RUN go build -ldflags "${SERVER_LDFLAGS}" ./cmd/rekor-server
 RUN CGO_ENABLED=0 go build -gcflags "all=-N -l" -ldflags "${SERVER_LDFLAGS}" -o rekor-server_debug ./cmd/rekor-server
 
 # Multi-Stage production build
-FROM golang:1.18.3@sha256:a452d6273ad03a47c2f29b898d6bb57630e77baf839651ef77d03e4e049c5bf3 as deploy
+FROM golang:1.18.4@sha256:9349ed889adb906efa5ebc06485fe1b6a12fb265a01c9266a137bb1352565560 as deploy
 
 # Retrieve the binary from the previous stage
 COPY --from=builder /opt/app-root/src/rekor-server /usr/local/bin/rekor-server