all: update descriptor.proto to latest version

A recent change to the upstream descriptor.proto, appearing in
google.golang.org/protobuf@v1.33.0, 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.

Increase the minimum Go version requirement to go1.17 (the minimum
supported by v1.33.0).

For #1596

.github/workflows/test.yml

@@ -4,7 +4,7 @@ jobs:
   test:
     strategy:
       matrix:
-        go-version: [1.11.x, 1.12.x, 1.13.x, 1.14.x, 1.15.x, 1.16.x]
+        go-version: [1.17.x, 1.18.x, 1.19.x, 1.20.x, 1.21.x]
         os: [ubuntu-latest, macos-latest]
     runs-on: ${{ matrix.os }}
     steps:
@@ -15,8 +15,8 @@ jobs:
     - name: Checkout code
       uses: actions/checkout@v2
     - name: TestLatest
-      if: matrix.go-version == '1.16.x'
+      if: matrix.go-version == '1.21.x'
       run: ./test.bash
     - name: TestAll
-      if: matrix.go-version != '1.16.x'
+      if: matrix.go-version != '1.21.x'
       run: go test ./...

go.mod

@@ -1,9 +1,9 @@
 // Deprecated: Use the "google.golang.org/protobuf" module instead.
 module github.com/golang/protobuf
 
-go 1.9
+go 1.17
 
 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=