protover: Vote for additional protocols to be required/recommended

Note that the changes here will require all relays
to be 0.4.7.4-alpha or later, which is lower than
our current lowest-supported relay version.

Part of #40836.

changes/ticket40836

+  o Minor features (required protocols):
+    - Directory authorities now vote to require relays to support certain
+      protocols, all of which have been implemented since 0.4.7.4-alpha or
+      earlier.
+      These include improved support for connecting to relays on IPv6,
+      NtorV3, running as a rate-limited introduction point,
+      authenticated SENDMEs, and congestion control.
+      Part of ticket 40836.
+
+  o Minor features (recommended protocols):
+    - Directory authorities now vote to recommend that clients
+      support certain protocols beyond those that are required.
+      These include improved support for connecting to relays on IPv6,
+      NtorV3, and congestion control.
+      Part of ticket 40836.

src/core/or/protover.c

@@ -521,8 +521,8 @@ protover_get_supported_protocols(void)
 const char *
 protover_get_recommended_client_protocols(void)
 {
-  return "Cons=2 Desc=2 DirCache=2 HSDir=2 HSIntro=4 HSRend=2 "
-         "Link=4-5 Microdesc=2 Relay=2";
+  return "Cons=2 Desc=2 DirCache=2 FlowCtrl=1-2 HSDir=2 HSIntro=4 HSRend=2 "
+         "Link=4-5 Microdesc=2 Relay=2-4";
 }
 
 /** Return the recommended relay protocols list that directory authorities
@@ -530,8 +530,8 @@ protover_get_recommended_client_protocols(void)
 const char *
 protover_get_recommended_relay_protocols(void)
 {
-  return "Cons=2 Desc=2 DirCache=2 HSDir=2 HSIntro=4 HSRend=2 "
-         "Link=4-5 LinkAuth=3 Microdesc=2 Relay=2";
+  return "Cons=2 Desc=2 DirCache=2 FlowCtrl=1-2 HSDir=2 HSIntro=4-5 HSRend=2 "
+         "Link=4-5 LinkAuth=3 Microdesc=2 Relay=2-4";
 }
 
 /** Return the required client protocols list that directory authorities
@@ -547,8 +547,8 @@ protover_get_required_client_protocols(void)
 const char *
 protover_get_required_relay_protocols(void)
 {
-  return "Cons=2 Desc=2 DirCache=2 HSDir=2 HSIntro=4 HSRend=2 "
-         "Link=4-5 LinkAuth=3 Microdesc=2 Relay=2";
+  return "Cons=2 Desc=2 DirCache=2 FlowCtrl=1-2 HSDir=2 HSIntro=4-5 HSRend=2 "
+         "Link=4-5 LinkAuth=3 Microdesc=2 Relay=2-4";
 }
 
 /*