Remove usage of deprecated APIs

[trivikr]

Issue #, if available:
N/A

Description of changes:
Removes usage of deprecated APIs

Before

$ smithy-typescript> ./gradlew publishToMavenLocal

> Task :smithy-typescript-codegen:compileJava
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.

[Incubating] Problems report is available at: file:///local/home/trivikr/workspace/smithy-typescript/build/reports/problems/problems-report.html

BUILD SUCCESSFUL in 3s

After

$ smithy-typescript> ./gradlew publishToMavenLocal

BUILD SUCCESSFUL in 7s

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[kuhe]

I think it should be this:

no codegen diff in all aws sdks?

    @Override
    public String timestampShape(TimestampShape shape) {
        Format format = shape.getMemberTrait(context.getModel(), TimestampFormatTrait.class)
            .map(TimestampFormatTrait::getFormat)
            .orElse(defaultTimestampFormat);
        
        return HttpProtocolGeneratorUtils.getTimestampInputParam(context, dataSource, shape, format);
    }