s3-lambda-bedrock: Update runtime to python3.13

[kakakakakku]

Issue #, if available:
N/A

Description of changes:
Hi😀 Thanks for the useful patterns!

To prevent future deployment issues, I updated the Lambda runtime python3.9 to python3.13.
The python3.9 runtime is scheduled to be deprecated in December.
See https://docs.aws.amazon.com/lambda/latest/dg/lambda-runtimes.html

Check

sam deploy completed successfully and works good.

$ aws s3 cp sampletext.txt s3://kakakakakku-s3-lambda-bedrock/content/
upload: ./sampletext.txt to s3://kakakakakku-s3-lambda-bedrock/content/sampletext.txt

$ aws logs tail "/aws/lambda/BedrockEmb" --follow --format json

(snip)

2025-11-17T01:39:36.176000+00:00 2025/11/17/[$LATEST]e9653705b7934fe79427d654fd2cc996 Response:
2025-11-17T01:39:36.177000+00:00 2025/11/17/[$LATEST]e9653705b7934fe79427d654fd2cc996 {'embedding': [-0.263671875, 0.1201171875, 0.34375, 0.2314453125, 0.042236328125, 0.2431640625, -0.345703125, 3.981590270996094e-05, 0.047119140625, -0.3828125, 0.19921875, 0.1201171875, 0.2001953125, 0.2109375, -0.375, 0.07666015625, -0.06787109375, 0.5078125, 0.0009765625, -0.07666015625, -0.26953125, 0.0927734375, -0.236328125, -0.07421875, 0.42578125, ... (snip)

Thank you😀

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