Update documentation to remove obsolete bind9-bugs@isc.org email address

README

@@ -50,19 +50,21 @@ bind9/releasenotes
 
 Reporting bugs and getting help
 
-Please report assertion failure errors and suspected security issues to
-security-officer@isc.org.
+To report non-security-sensitive bugs or request new features, you may
+open an Issue in the BIND 9 project on the ISC GitLab server at https://
+gitlab.isc.org/isc-projects/bind9.
 
-General bug reports can be sent to bind9-bugs@isc.org.
+Please note that, unless you explicitly mark the newly created Issue as
+"confidential", it will be publicly readable. Please do not include any
+information in bug reports that you consider to be confidential unless the
+issue has been marked as such. In particular, if submitting the contents
+of your configuration file in a non-confidential Issue, it is advisable to
+obscure key secrets: this can be done automatically by using
+named-checkconf -px.
 
-Feature requests can be sent to bind-suggest@isc.org.
-
-Please note that, while tickets submitted to ISC's ticketing system are
-not initially publicly readable by default, they can be made publicly
-acessible afterward. Please do not include information in bug reports that
-you consider to be confidential. In particular, when sending the contents
-of your configuration file, it is advisable to obscure key secrets: this
-can be done automatically by using named-checkconf -px.
+If the bug you are reporting is a potential security issue, such as an
+assertion failure or other crash in named, please do NOT use GitLab to
+report it. Instead, please send mail to security-officer@isc.org.
 
 Professional support and training for BIND are available from ISC at
 https://www.isc.org/support.
@@ -83,11 +85,17 @@ Information for BIND contributors can be found in the following files: -
 General information: CONTRIBUTING.md - BIND 9 code style: doc/dev/style.md
 - BIND architecture and developer guide: doc/dev/dev.md
 
-Patches for BIND may be submitted either as Github pull requests or via
-email. When submitting a patch via email, please prepend the subject
-header with "[PATCH]" so it will be easier for us to find. If your patch
-introduces a new feature in BIND, please submit it to bind-suggest@isc.org
-; if it fixes a bug, please submit it to bind9-bugs@isc.org.
+Patches for BIND may be submitted as Merge Requests in the ISC GitLab
+server at at https://gitlab.isc.org/isc-projects/bind9/merge_requests.
+
+By default, external contributors don't have ability to fork BIND in the
+GitLab server, but if you wish to contribute code to BIND, you may request
+permission to do so. Thereafter, you can create git branches and directly
+submit requests that they be reviewed and merged.
+
+If you prefer, you may also submit code by opening a GitLab Issue and
+including your patch as an attachment, preferably generated by git
+format-patch.
 
 BIND 9.13 features
 
@@ -324,4 +332,3 @@ Acknowledgments
     (eay@cryptsoft.com)
   * This product includes software written by Tim Hudson
     (tjh@cryptsoft.com)
-