all: update descriptor.proto to latest version

A recent change to the upstream descriptor.proto, appearing in
google.golang.org/[email protected], removed the long-deprecated
FileOptions.php_generic_services field. This backwards-incompatible
change results in an incompatibility between the
github.com/golang/protobuf and google.golang.org/protobuf
modules.

Bump the google.golang.org/protobuf version in go.mod, regenerate
descriptors.

For #1596

Author: neild

go.mod

@@ -5,5 +5,5 @@ go 1.9
 
 require (
 	github.com/google/go-cmp v0.5.5
-	google.golang.org/protobuf v1.26.0
+	google.golang.org/protobuf v1.33.0
 )

go.sum

@@ -6,3 +6,5 @@ golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8T
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
 google.golang.org/protobuf v1.26.0 h1:bxAC2xTBsZGibn2RTntX0oH50xLsqy1OxA9tTL3p/lk=
 google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
+google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGmI=
+google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=