{README,CONTRIBUTIONS}.md: Add link to binaries from latest commit

Author: oech3

CONTRIBUTING.md

@@ -78,11 +78,11 @@ issues and writing documentation are just as important as writing code.
 We can't fix bugs we don't know about, so good issues are super helpful! Here
 are some tips for writing good issues:
 
-- If you find a bug, make sure it's still a problem on the `main` branch.
+- If you find a bug, make sure it's still a problem on the [`main` branch](https://github.com/uutils/coreutils/releases/tag/latest-commit).
 - Search through the existing issues to see whether it has already been
   reported.
 - Make sure to include all relevant information, such as:
-  - Which version of uutils did you check?
+  - Which version or commit hash of uutils did you check?
   - Which version of GNU coreutils are you comparing with?
   - What platform are you on?
 - Provide a way to reliably reproduce the issue.

README.md

@@ -29,8 +29,9 @@ options might be missing or different behavior might be experienced.
 
 <div class="oranda-hide">
 
-We provide prebuilt binaries at https://github.com/uutils/coreutils/releases/latest .
-It is recommended to install from main branch if you install from source.
+We provide prebuilt binaries, manpages, and shell completions at https://github.com/uutils/coreutils/releases/tag/latest-commit .
+The latest stable tag https://github.com/uutils/coreutils/releases/latest exists only for reproducible products and packagers.
+You should use binary from latest commit generally.
 
 </div>