chore: remove staging bucket v2

not needed since we removed v2 solution - googleapis/synthtool#964

Source-Author: Emily Ball <emilyball@google.com>
Source-Date: Mon Mar 29 14:47:37 2021 -0700
Source-Repo: googleapis/synthtool
Source-Sha: 572ef8f70edd9041f5bcfa71511aed6aecfc2098
Source-Link: googleapis/synthtool@572ef8f

.kokoro/release/publish_javadoc.sh

@@ -24,11 +24,6 @@ if [[ -z "${STAGING_BUCKET}" ]]; then
   exit 1
 fi
 
-if [[ -z "${STAGING_BUCKET_V2}" ]]; then
-  echo "Need to set STAGING_BUCKET_V2 environment variable"
-  exit 1
-fi
-
 # work from the git root directory
 pushd $(dirname "$0")/../../
 

synth.metadata

@@ -11,7 +11,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "d0bdade9a962042dc0f770cf631086f3db59b5b0"
+        "sha": "572ef8f70edd9041f5bcfa71511aed6aecfc2098"
       }
     }
   ],