fix: builder/Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DEBIAN10-CURL-3065760
- https://snyk.io/vuln/SNYK-DEBIAN10-EXPAT-2406128
- https://snyk.io/vuln/SNYK-DEBIAN10-LIBBSD-541041
- https://snyk.io/vuln/SNYK-DEBIAN10-SYSTEMD-3339153
- https://snyk.io/vuln/SNYK-DEBIAN10-SYSTEMD-3339153

builder/Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM golang:1.14
+FROM golang:1.20.8
 LABEL maintainer="Marcin Wielgus <[email protected]>"
 
 ENV GOPATH /gopath/