Upgrade appengine (#8046)

Author: sigurdm

app/pubspec.lock

@@ -55,10 +55,10 @@ packages:
     dependency: "direct main"
     description:
       name: appengine
-      sha256: "58b6f4444d31f30afa206b4bb0bb6e3399e31dbc79a11ff49804ce5d0a1a0e0c"
+      sha256: "85cf49b3de9fc027cfb551c8ee80b69448ff05d356aea57e73f17088cb252a8a"
       url: "https://pub.dev"
     source: hosted
-    version: "0.13.7"
+    version: "0.13.8"
   archive:
     dependency: transitive
     description:
@@ -605,10 +605,10 @@ packages:
     dependency: transitive
     description:
       name: protobuf
-      sha256: "01dd9bd0fa02548bf2ceee13545d4a0ec6046459d847b6b061d8a27237108a08"
+      sha256: "68645b24e0716782e58948f8467fd42a880f255096a821f9e7d0ec625b00c84d"
       url: "https://pub.dev"
     source: hosted
-    version: "2.1.0"
+    version: "3.1.0"
   pub_package_reader:
     dependency: "direct main"
     description:

app/pubspec.yaml

@@ -7,7 +7,7 @@ dependencies:
     path: ../pkg/_popularity
   _pub_shared:
     path: ../pkg/_pub_shared
-  appengine: ^0.13.6
+  appengine: ^0.13.8
   args: '^2.0.0'
   basics: ^0.10.0
   chunked_stream: ^1.1.0