Add spring_version variable to have single instance of spring version

[cwperks]

Description

Extracts spring_version to a variable so it can be re-used. This will cut down slightly on maintenance where dependabot can make multiple PRs to update this version.

Recent examples:

• Bump org.springframework:spring-core from 5.3.30 to 5.3.31 #3744
• Bump org.springframework:spring-beans from 5.3.30 to 5.3.31 #3743

• Category (Enhancement, New feature, Bug fix, Test fix, Refactoring, Maintenance, Documentation)

Maintenance

Check List

• New functionality includes testing
• New functionality has been documented
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov]

Codecov Report

Merging #3747 (e148414) into main (4496440) will decrease coverage by 0.01%.
Report is 5 commits behind head on main.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3747      +/-   ##
==========================================
- Coverage   65.23%   65.22%   -0.01%     
==========================================
  Files         297      297              
  Lines       21129    21129              
  Branches     3451     3451              
==========================================
- Hits        13783    13782       -1     
  Misses       5647     5647              
- Partials     1699     1700       +1     

see 1 file with indirect coverage changes

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/security/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/security/backport-2.x
# Create a new branch
git switch --create backport/backport-3747-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 daa584d80705fd6ee254716dc8342df4cc6dbbd1
# Push it to GitHub
git push --set-upstream origin backport/backport-3747-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/security/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-3747-to-2.x.