chore: update github-merit-badger.yml (#30950)

### Issue # (if applicable)
N/A

### Reason for this change
Add `ashishdhingra` to ignore list for merit badger.

### Description of changes
Add `ashishdhingra` to ignore list for merit badger.

### Description of how you validated changes


### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

.github/workflows/github-merit-badger.yml

@@ -17,4 +17,4 @@ jobs:
           badges: '[beginning-contributor,repeat-contributor,valued-contributor,admired-contributor,star-contributor,distinguished-contributor]'
           thresholds: '[0,3,6,13,25,50]'
           badge-type: 'achievement'
-          ignore-usernames: '[rix0rrr,iliapolo,otaviomacedo,kaizencc,comcalvi,TheRealAmazonKendra,vinayak-kukreja,mrgrain,pahud,cgarvis,kellertk,HBobertz,sumupitchayan,SankyRed,udaypant,colifran,khushail,scanlonp,mikewrighton,moelasmar,paulhcsun,awsmjs,evgenyka,GavinZZ,aaythapa,xazhao,ConnorRobertson,ssenchenko,gracelu0,jfuss,SimonCMoore,shikha372,kirtishrinkhala,godwingrs22,bergjaak,IanKonlog,Leo10Gama,samson-keung,scorbiere,aws-cdk-automation,dependabot[bot],mergify[bot]]'
+          ignore-usernames: '[rix0rrr,iliapolo,otaviomacedo,kaizencc,comcalvi,TheRealAmazonKendra,vinayak-kukreja,mrgrain,pahud,cgarvis,kellertk,ashishdhingra,HBobertz,sumupitchayan,SankyRed,udaypant,colifran,khushail,scanlonp,mikewrighton,moelasmar,paulhcsun,awsmjs,evgenyka,GavinZZ,aaythapa,xazhao,ConnorRobertson,ssenchenko,gracelu0,jfuss,SimonCMoore,shikha372,kirtishrinkhala,godwingrs22,bergjaak,IanKonlog,Leo10Gama,samson-keung,scorbiere,aws-cdk-automation,dependabot[bot],mergify[bot]]'