[BUG] `update-version.sh` incorrectly mutates a few (non-important) values

[gforsyth]

As part of the 26.08 release, tracked in https://github.com/rapidsai/ops/issues/4676

during the release of this repo, I noticed the following diff in the CONTRIBUTING.md file:

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 9aae81a..cc17d03 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -24,7 +24,7 @@ export LINUX_VER=ubuntu24.04
 export PYTHON_VER=3.14

 # RAPIDS version in {major}.{minor}
-export RAPIDS_VER=26.06
+export RAPIDS_VER=26.086

 # rapidsai/base
 docker build $(ci/compute-build-args.sh) \

Now obviously that's wrong, but it wasn't worth a hotfix, but we should clean it up on main (make sure that update-version.sh does the right thing).

[arcusbuilds]

I would like to work on it.