Bump Go version to v1.20 (#24439)

server/build/Dockerfile.buildenv

@@ -1,3 +1,3 @@
-FROM golang:1.19.5@sha256:bb9811fad43a7d6fd2173248d8331b2dcf5ac9af20976b1937ecd214c5b8c383
+FROM golang:1.20.7-bullseye@sha256:c95c52c458a2678251e0769ea13c710b0c52814771c53a495f53b9e87f9c0e99
 
 RUN apt-get update && apt-get install -y make git apt-transport-https ca-certificates curl software-properties-common build-essential zip xmlsec1 jq