Move azure variable to env variable

Signed-off-by: Matthew B White <whitemat@uk.ibm.com>

ci/templates/nightly-version-update.yaml

@@ -1,12 +1,13 @@
 steps:
 - script: |
     set -ev 
-    export RELEASE_VERSION=${VERSION}-unstable.$(Date:yyyyMMdd)
+    export RELEASE_VERSION=${VERSION}.dev.${DATE_STAMP}
     find . \( -wholename "./docs/package.json" -or -wholename "./apis/**/package.json" -or -wholename "./libraries/**/package.json" -or -wholename "./test/**/package.json" \) -exec node ci/updatePackageJson.js {} \;
     node common/scripts/install-run-rush.js update      
   name: UpdateVersionNightlyDrivers
-  displayName: 'Build data'
+  displayName: 'Update Version for dev drivers'
   condition: and(succeeded(), eq(variables['Build.Reason'], 'Schedule'))  # only run on the scheduled builds
   env:
     COMMIT_ID: $(Build.SourceVersion)
-    VERSION: $(VERSION) 
+    VERSION: $(VERSION) 
+    DATE_STAMP: $(Date:yyyyMMdd)