build: replace tag separator / (slash) with - (hyphen) (#1004)

Replace tag separator / with -

See issue for more information #981
Dependabot and Renovate seem to follow a "namespaced" solution when it comes to tagging
versions in monorepos. We should try to follow that to make automated updates smoother

Author: dsotirakis

release-please-config.json

@@ -145,5 +145,6 @@
     }
   },
   "release-type": "simple",
+  "tag-separator": "/",
   "separate-pull-requests": true
 }