Update release_docs HISTORY scheme (#2443)

We will no longer maintain HISTORY files for other maintenance branches,
so those have been removed. Adds a README.md explaining the purpose
and procedures of HDF5 HISTORY. Also adds a newsletter template and
updates the RELEASE.txt note part of CONTRIBUTING.md.

Also cleans out RELEASE.txt post-HDF5-1.14.0

1 files changed, 25 insertions, 0 deletions

diff --git a/release_docs/NEWSLETTER.txt b/release_docs/NEWSLETTER.txt
new file mode 100644
index 0000000..f03f710
--- /dev/null
+++ b/release_docs/NEWSLETTER.txt
@@ -0,0 +1,25 @@
+INTRODUCTION
+============
+
+This purpose of this document is to contain entries that can be used to quickly
+produce a release newsletter. When something is added to the library that is
+"newsletter worthy" (i.e., new feature, CVE fix, etc.) a summary note should
+be added here.
+
+The format should look like this:
+
+* SUMMARY OF NEWSLETTER-WORTHY THING
+
+    Here is where you describe the summary. Summarize the feature, fix, or
+    change in general language. Remember, RELEASE.txt is for communicating
+    technical specifics. Text entered here is more like advertising.
+
+    (GitHub #123, #125)
+
+The GitHub #s could be relevant issues or PRs. They will probably not appear
+in the final newsletter, but are so that the person writing the newsletter
+has easy access to context if they have questions.
+
+Every entry in RELEASE.txt does NOT require an entry here. The newsletter is
+for communicating major changes that are of interest to anyone. Minor bugfixes,
+memory leak fixes, etc. do not require entries.