PHPC-2013: Upgrade libmongoc to 1.21.0

Pulls in changes from CDRIVER-4237

Also addresses min/maxWireVersion bumps for PHPC-1909 and PHPC-2034.

Author: jmikola

.evergreen/config.yml

@@ -1157,19 +1157,16 @@ axes:
   - id: libmongoc-version
     display_name: libmongoc version
     values:
-      # TODO: enable lowest-supported and upcoming-stable after 1.20.0 is
-      # released and r1.20 is branched. As-is, r1.19 cannot be compiled because
-      # PHP_MONGODB_MONGOC_SOURCES conflicts with 1.20-dev (see: PHPC-2006).
-      #- id: "lowest-supported"
-      #  display_name: "1.19.1"
-      #  variables:
-      #    LIBMONGOC_VERSION: "1.19.1"
-      #- id: "upcoming-stable"
-      #  display_name: "1.19-dev"
-      #  variables:
-      #    LIBMONGOC_VERSION: "r1.19"
+      - id: "lowest-supported"
+        display_name: "1.21.0"
+        variables:
+          LIBMONGOC_VERSION: "1.21.0"
+      - id: "upcoming-stable"
+        display_name: "1.21-dev"
+        variables:
+          LIBMONGOC_VERSION: "r1.21"
       - id: "latest-dev"
-        display_name: "1.20-dev (master)"
+        display_name: "1.22-dev (master)"
         variables:
           LIBMONGOC_VERSION: "master"
 

src/LIBMONGOC_VERSION_CURRENT

@@ -1 +1 @@
-1.11.1-20220104+gite7e15002d6
+1.21.0