chore: add saiyush to core contributors (aws#32030)

### Reason for this change

Include @saiyush to list of core contributors.

### Description of how you validated changes

Copy-pasted the username verbatim.

### 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,mrgrain,pahud,kellertk,ashishdhingra,HBobertz,sumupitchayan,colifran,khushail,moelasmar,paulhcsun,GavinZZ,aaythapa,xazhao,gracelu0,jfuss,shikha372,kirtishrinkhala,godwingrs22,bergjaak,IanKonlog,Leo10Gama,samson-keung,scorbiere,michelle-wangg,jiayiwang7,1kaileychen,aws-cdk-automation,dependabot[bot],mergify[bot]]'
+          ignore-usernames: '[rix0rrr,iliapolo,otaviomacedo,kaizencc,comcalvi,TheRealAmazonKendra,mrgrain,pahud,kellertk,ashishdhingra,HBobertz,sumupitchayan,colifran,khushail,moelasmar,paulhcsun,GavinZZ,aaythapa,xazhao,gracelu0,jfuss,shikha372,kirtishrinkhala,godwingrs22,bergjaak,IanKonlog,Leo10Gama,samson-keung,scorbiere,michelle-wangg,jiayiwang7,1kaileychen,saiyush,aws-cdk-automation,dependabot[bot],mergify[bot]]'

.mergify.yml

@@ -43,7 +43,7 @@ pull_request_rules:
       label:
         add: [ contribution/core ]
     conditions:
-      - author~=^(rix0rrr|iliapolo|otaviomacedo|kaizencc|comcalvi|TheRealAmazonKendra|mrgrain|pahud|ashishdhingra|kellertk|HBobertz|sumupitchayan|colifran|moelasmar|paulhcsun|GavinZZ|aaythapa|xazhao|gracelu0|jfuss|shikha372|kirtishrinkhala|godwingrs22|bergjaak|samson-keung|IanKonlog|Leo10Gama|scorbiere|michelle-wangg|jiayiwang7|1kaileychen)$
+      - author~=^(rix0rrr|iliapolo|otaviomacedo|kaizencc|comcalvi|TheRealAmazonKendra|mrgrain|pahud|ashishdhingra|kellertk|HBobertz|sumupitchayan|colifran|moelasmar|paulhcsun|GavinZZ|aaythapa|xazhao|gracelu0|jfuss|shikha372|kirtishrinkhala|godwingrs22|bergjaak|samson-keung|IanKonlog|Leo10Gama|scorbiere|michelle-wangg|jiayiwang7|1kaileychen|saiyush)$
       - -label~="contribution/core"
   - name: automatic merge
     actions: