(PUP-11699) Support ruby-openssl 3 immutable keys

OpenSSL::PKey instances are now immutable in ruby-openssl 3. So set the EC key
directly on the certificate request instead of creating a new instance.

Author: joshcooper

lib/puppet/ssl/certificate_request.rb

@@ -68,10 +68,7 @@ def generate(key, options = {})
     csr.public_key = if key.is_a?(OpenSSL::PKey::EC)
                        # EC#public_key doesn't follow the PKey API,
                        # see https://github.com/ruby/openssl/issues/29
-                       point = key.public_key
-                       pubkey = OpenSSL::PKey::EC.new(point.group)
-                       pubkey.public_key = point
-                       pubkey
+                       key
                      else
                        key.public_key
                      end