feat: Support HTTP schemes

[MicahParks]

This pull request expands the supported URL schemes in the parseTarget function to include both HTTP and HTTPS, in addition to the existing gRPC schemes. It updates the scheme validation logic, adjusts default ports and TLS verification accordingly, and improves error handling. The test suite is also updated to cover the new supported schemes and error scenarios.

Expanded protocol support and validation:

• Added support for http and https schemes in parseTarget, updating the allowedSchemesRe regular expression and related logic to accept these schemes. [1] [2]
• Introduced a new error variable ErrInvalidTargetScheme for consistent error handling when an unsupported scheme is encountered. [1] [2]

Connection handling improvements:

• Adjusted default port assignment: grpc and http default to port 80, grpcs and https default to port 443 if the port is not specified.
• Updated TLS verification logic: enabled for grpcs and https, disabled for grpc and http.

Test coverage enhancements:

• Added new test cases for valid http and https targets, including correct port and TLS verification expectations.
• Updated the invalid scheme test case to use an unsupported scheme (ftp) and expect the new ErrInvalidTargetScheme error.

[github-actions]

Go test coverage

STATUS	ELAPSED	PACKAGE	COVER	PASS	FAIL	SKIP
🟢 PASS	0.00s	github.com/netboxlabs/diode-sdk-go/cmd/diode-replay-dryrun	0.0%	0	0	0
🟢 PASS	1.29s	github.com/netboxlabs/diode-sdk-go/diode	20.4%	220	0	0

Total coverage: 75.8%

[jajeffries]

LGTM - same comment about breaking changes as here, but I think fine in this case.