Revert "Bump webpush from 0.3.8 to 1.0.0 (#11614)" (#11840)

This reverts commit 9045f5e3f8.

Gemfile.lock

@@ -321,7 +321,7 @@ GEM
       multi_json (~> 1.12)
       rdf (~> 3.0)
     jsonapi-renderer (0.2.2)
-    jwt (2.2.1)
+    jwt (2.1.0)
     kaminari (1.1.1)
       activesupport (>= 4.1.0)
       kaminari-actionview (= 1.1.1)
@@ -654,7 +654,7 @@ GEM
       activesupport (>= 4.2)
       rack-proxy (>= 0.6.1)
       railties (>= 4.2)
-    webpush (1.0.0)
+    webpush (0.3.8)
       hkdf (~> 0.2)
       jwt (~> 2.0)
     websocket-driver (0.7.0)