fix: add missing max-retries input to csharp-publish

Add missing max-retries input declaration that was being used by the
step-security/retry step at line 171 but not defined in the inputs
section.

Changes:
- Add max-retries input with default value of '3'
- Add description for dependency restoration retry attempts
- Regenerate README.md with updated inputs documentation

This fixes undefined input reference in the Restore Dependencies step.

csharp-publish/rules.yml

@@ -2,7 +2,7 @@
 # Validation rules for csharp-publish action
 # Generated by update-validators.py v1.0.0 - DO NOT EDIT MANUALLY
 # Schema version: 1.0
-# Coverage: 100% (3/3 inputs)
+# Coverage: 100% (4/4 inputs)
 #
 # This file defines validation rules for the csharp-publish GitHub Action.
 # Rules are automatically applied by validate-inputs action when this
@@ -17,15 +17,17 @@ required_inputs:
   - namespace
 optional_inputs:
   - dotnet-version
+  - max-retries
   - token
 conventions:
   dotnet-version: dotnet_version
+  max-retries: numeric_range_1_10
   namespace: namespace_with_lookahead
   token: github_token
 overrides: {}
 statistics:
-  total_inputs: 3
-  validated_inputs: 3
+  total_inputs: 4
+  validated_inputs: 4
   skipped_inputs: 0
   coverage_percentage: 100
 validation_coverage: 100