Revert "Bump go.mongodb.org/mongo-driver from 1.11.6 to 1.12.0 (#4614)"

This reverts commit 14adbb88fe.

go.mod

@@ -107,7 +107,7 @@ require (
 	github.com/xdg-go/stringprep v1.0.4 // indirect
 	github.com/youmark/pkcs8 v0.0.0-20201027041543-1326539a0a0a // indirect
 	go.etcd.io/etcd/client/v3 v3.5.9
-	go.mongodb.org/mongo-driver v1.12.0
+	go.mongodb.org/mongo-driver v1.11.6
 	go.opencensus.io v0.24.0 // indirect
 	gocloud.dev v0.29.0
 	gocloud.dev/pubsub/natspubsub v0.29.0

go.sum

@@ -2282,8 +2282,8 @@ go.mongodb.org/mongo-driver v1.7.5/go.mod h1:VXEWRZ6URJIkUq2SCAyapmhH0ZLRBP+FT4x
 go.mongodb.org/mongo-driver v1.8.3/go.mod h1:0sQWfOeY63QTntERDJJ/0SuKK0T1uVSgKCuAROlKEPY=
 go.mongodb.org/mongo-driver v1.10.0/go.mod h1:wsihk0Kdgv8Kqu1Anit4sfK+22vSFbUrAVEYRhCXrA8=
 go.mongodb.org/mongo-driver v1.11.0/go.mod h1:s7p5vEtfbeR1gYi6pnj3c3/urpbLv2T5Sfd6Rp2HBB8=
-go.mongodb.org/mongo-driver v1.12.0 h1:aPx33jmn/rQuJXPQLZQ8NtfPQG8CaqgLThFtqRb0PiE=
-go.mongodb.org/mongo-driver v1.12.0/go.mod h1:AZkxhPnFJUoH7kZlFkVKucV20K387miPfm7oimrSmK0=
+go.mongodb.org/mongo-driver v1.11.6 h1:XM7G6PjiGAO5betLF13BIa5TlLUUE3uJ/2Ox3Lz1K+o=
+go.mongodb.org/mongo-driver v1.11.6/go.mod h1:G9TgswdsWjX4tmDA5zfs2+6AEPpYJwqblyjsfuh8oXY=
 go.mozilla.org/pkcs7 v0.0.0-20200128120323-432b2356ecb1/go.mod h1:SNgMg+EgDFwmvSmLRTNKC5fegJjB7v23qTQ0XLGUNHk=
 go.opencensus.io v0.15.0/go.mod h1:UffZAU+4sDEINUGP/B7UfBBkq4fqLu9zXAX7ke6CHW0=
 go.opencensus.io v0.21.0/go.mod h1:mSImk1erAIZhrmZN+AvHh14ztQfjbGwt4TtuofqLduU=