feat(sources/s3): migrate to AWS SDK v2 (#4069)

Closes #4054.

This PR migrates the S3 source to use AWS SDK v2 by following the migration guide https://docs.aws.amazon.com/sdk-for-go/v2/developer-guide/migrate-gosdk.html. This brings compatibility improvements and better long-term support from AWS.

To verify the changes manually, I:

Created a test S3 bucket.
Uploaded sample files containing dummy secrets.
Set up an IAM role for access.
Ran trufflehog s3 and confirmed it behaves as expected post-migration.

additional notes by @rosecodym: The existing S3 automated tests passed, modulo some flakiness that we will address in a follow-up commit.

Author: Juneezee

go.mod

@@ -19,10 +19,11 @@ require (
 	github.com/adrg/strutil v0.3.1
 	github.com/alecthomas/kingpin/v2 v2.4.0
 	github.com/avast/apkparser v0.0.0-20250307094510-e2100ee9c0f5
-	github.com/aws/aws-sdk-go v1.55.6
 	github.com/aws/aws-sdk-go-v2 v1.36.3
 	github.com/aws/aws-sdk-go-v2/config v1.29.14
 	github.com/aws/aws-sdk-go-v2/credentials v1.17.67
+	github.com/aws/aws-sdk-go-v2/feature/s3/manager v1.17.75
+	github.com/aws/aws-sdk-go-v2/service/s3 v1.79.3
 	github.com/aws/aws-sdk-go-v2/service/sns v1.34.4
 	github.com/aws/aws-sdk-go-v2/service/sts v1.33.19
 	github.com/aws/smithy-go v1.22.3
@@ -150,12 +151,16 @@ require (
 	github.com/andybalholm/brotli v1.1.1 // indirect
 	github.com/apache/arrow/go/v14 v14.0.2 // indirect
 	github.com/atotto/clipboard v0.1.4 // indirect
+	github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.6.10 // indirect
 	github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.16.30 // indirect
 	github.com/aws/aws-sdk-go-v2/internal/configsources v1.3.34 // indirect
 	github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.6.34 // indirect
 	github.com/aws/aws-sdk-go-v2/internal/ini v1.8.3 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/v4a v1.3.34 // indirect
 	github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.12.3 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/checksum v1.7.1 // indirect
 	github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.12.15 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/s3shared v1.18.15 // indirect
 	github.com/aws/aws-sdk-go-v2/service/sso v1.25.3 // indirect
 	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.30.1 // indirect
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
@@ -231,7 +236,6 @@ require (
 	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
 	github.com/hashicorp/go-multierror v1.1.1 // indirect
 	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
-	github.com/jmespath/go-jmespath v0.4.0 // indirect
 	github.com/jpillora/s3 v1.1.4 // indirect
 	github.com/kevinburke/ssh_config v1.2.0 // indirect
 	github.com/kjk/lzma v0.0.0-20161016003348-3fd93898850d // indirect