Add v0.13.0 entry in doc/_static/version_switch.js for documentation switcher

Author: seisman

doc/_static/version_switch.js

@@ -12,6 +12,7 @@
   var all_versions = {
     'latest': 'latest',
     'dev': 'dev',
+    'v0.13.0': 'v0.13.0',
     'v0.12.0': 'v0.12.0',
     'v0.11.0': 'v0.11.0',
     'v0.10.0': 'v0.10.0',