ci: offset atlasbot build numbers

Jenkinsfile

@@ -119,8 +119,13 @@ spec:
             sh 'git config --global --add safe.directory /home/jenkins/agent/workspace/atlasbot'
             def semver = sh(returnStdout: true, script: 'git describe --tags --exact-match || true').trim()
             if (!semver) {
-              semver = sh(returnStdout: true, script: 'git rev-list --count HEAD').trim()
-              semver = "0.1.0-${semver}"
+              def offset = sh(returnStdout: true, script: 'cat VERSION_OFFSET 2>/dev/null || true').trim()
+              if (!offset) {
+                offset = "0"
+              }
+              def count = sh(returnStdout: true, script: 'git rev-list --count HEAD').trim()
+              def versionNum = count.toInteger() + offset.toInteger()
+              semver = "0.1.0-${versionNum}"
             }
             sh "echo SEMVER=${semver} > build.env"
           }

VERSION_OFFSET

@@ -0,0 +1 @@
+20