Bump spring-core version, ignore 6.x in Dependabot updates

[akkomar]

This updates spring-core to latest 5.x version and configures Dependabot to ignore versions 6.x+.
Spring 6 requires Java 17 so we'd need to update JDK first.

This is a test-scope dependency, does not affect production.

closes #2650

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.78%. Comparing base (50925a1) to head (41ff1b4).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #2657   +/-   ##
=========================================
  Coverage     85.78%   85.78%           
  Complexity      873      873           
=========================================
  Files           118      118           
  Lines          4975     4975           
  Branches        502      502           
=========================================
  Hits           4268     4268           
  Misses          546      546           
  Partials        161      161           

Flag	Coverage Δ
ingestion_beam	83.23% <ø> (ø)

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