Enable https to Let's Encrypt endpoints by using an SSL factory with

the two extra Let's Encrypt root certs installed into an auxiliary
keystore.

The keystore was generated using standard commands, documented in the
FixSSL class.

The Let's Encrypt certificates are not provided by default in Java 8
prior to update 101.

Signed-off-by: cpw <cpw+github@weeksfamily.ca>

src/main/java/net/minecraftforge/fml/VersionChecker.java

@@ -271,7 +271,7 @@ public class VersionChecker
                 }
                 catch (Exception e)
                 {
-                    LOGGER.debug("Failed to process update information", e);
+                    LOGGER.warn("Failed to process update information", e);
                     status = FAILED;
                 }
                 results.put(mod, new CheckResult(status, target, changes, display_url));