Fix version switcher URLs

Author: jpfeuffer

docs/source/_static/switcher.json

@@ -7,17 +7,12 @@
   {
       "name": "3.3.0",
       "version": "3.3.0",
-      "url": "https://pyopenms.readthedocs.io/en/release3.3.0/"
+      "url": "https://pyopenms.readthedocs.io/en/release-3.3.0/"
   },
   {
       "name": "3.2.0",
       "version": "3.2.0",
-      "url": "https://pyopenms.readthedocs.io/en/release3.2.0/"
-  },
-  {
-      "name": "3.1.0",
-      "version": "3.1.0",
-      "url": "https://pyopenms.readthedocs.io/en/release3.1.0/"
+      "url": "https://pyopenms.readthedocs.io/en/release-3.2.0/"
   },
   {
       "name": "3.0.0",