NEWS.md: add 0.4.0 release notes

Problem: there are no release notes for flux-coral2 0.4.0.

Add them.

Author: jameshcorbett

NEWS.md

@@ -1,3 +1,29 @@
+flux-coral2 0.4.0 - 2023-04-07
+------------------------------
+
+### New Features
+
+ * dws: Rabbits are chosen based on compute nodes (#53)
+ * dws: Workflows in 'Error' state too long are now killed (#49)
+ * dws: hold jobs in epilog for data movement (#46)
+ * dws: support multiple DW directives in a single string (#54)
+ * dws: package coral2_dws.py as a systemd unit (#47)
+ * pals: support for `-o pmi=cray-pals` (#58)
+ * pals: added an rc script for loading port distributor in all Flux instances (#58)
+
+### Fixes
+
+ * dws: shorten workflow names to prevent DWS overflow errors (#39)
+ * build: add missing header file (#38)
+ * dws: improve error messages (#54)
+
+### Testsuite
+
+ * testsuite: update uses of `flux mini CMD` (#50)
+ * testsuite: add tests for jobtap prolog exceptions (#51)
+ * github: add 'make distcheck' to CI (#48)
+
+
 flux-coral2 0.3.0 - 2023-01-31
 ------------------------------