RUBY-2351 Increase minimum Ruby version to 2.4 (#2298)

Author: comandeo-mongo

source/reference/driver-compatibility.txt

@@ -45,6 +45,16 @@ The first column lists the driver versions.
      - MongoDB 3.0
      - MongoDB 2.6
 
+   * - 2.16
+     - |checkmark|
+     - |checkmark|
+     - |checkmark|
+     - |checkmark|
+     - |checkmark|
+     - |checkmark|
+     - |checkmark|
+     - |checkmark|
+
    * - 2.15
      - |checkmark|
      - |checkmark|
@@ -237,6 +247,20 @@ for that Ruby version is deprecated.
      - JRuby 9.1
      - JRuby
 
+   * - 2.16
+     - |checkmark|
+     - |checkmark|
+     - |checkmark|
+     - |checkmark|
+     - D
+     -
+     -
+     -
+     -
+     -
+     - |checkmark|
+     -
+     -
    * - 2.15
      - |checkmark|
      - |checkmark|

source/release-notes.txt

@@ -17,6 +17,11 @@ comprehensive list of changes in each version of the driver and the
 for the complete list of changes, including those internal to the driver and
 its test suite.
 
+2.16
+====
+
+This release of the Ruby driver increases the minimum required Ruby version
+to 2.4.
 
 2.15
 ====
@@ -65,7 +70,6 @@ The following smaller improvements have been made:
   ``writeErrors`` field in the server response.
 - Server selection timeout for ``mongocryptd`` has been increased to 10 seconds.
 
-
 2.14
 ====