add release notes for 0.19.0 release

NEWS

@@ -1,3 +1,34 @@
+* Release 0.19.0 (08 Apr 2024)
+
+New API:
+* `to_ssh` in `VerifyingKey` and `SigningKey`, supports Ed25519 keys only
+  (Pablo Mazzini)
+
+New features:
+* Support for twisted Brainpool curves
+
+Doc fix:
+* Fix curve equation in glossary
+* Documentation for signature encoding and signature decoding functions
+
+Maintenance:
+* Dropped official support for 3.3 and 3.4 (because of problems running them
+  in CI, not because it's actually incompatible; support for 2.6 and 2.7 is
+  unaffected)
+* Fixes aroung hypothesis parameters
+* Officially support Python 3.11 and 3.12
+* Small updates to test suite to make it work with 3.11 and 3.12 and new
+  releases of test dependencies
+* Dropped the internal `_rwlock` module as it's unused
+* Added mutation testing to CI, lots of speed-ups to the test suite
+  to make it happen
+* Removal of unnecessary `six.b` literals (Alexandre Detiste)
+
+Deprecations:
+* `int_to_string`, `string_to_int`, and `digest_integer` from `ecdsa.ecdsa`
+  module are now considered deprecated, they will be removed in a future
+  release
+
 * Release 0.18.0 (09 Jul 2022)
 
 New API: