add check for supported near-sdk version

[miraclx]

Fixes #29

Reduced the scope of errors from dep checking to 3.

1. unable to appropriately resolve the dependency graph, perhaps your `Cargo.toml` file is malformed
2. `near-sdk` dependency not found
3. unsupported `near-sdk` version. expected 4.1.* or higher

Hopefully they're descriptive enough.

Adapted the integration tests from #48.

[itegulov]

Also, you can remove #[ignore] from cargo::test_dependency_platform_specific. Seems like cargo metadata is choosing the right dependency depending on the target which is a cool side effect.

[itegulov]

In any case, the changes look good to me even as is. Going to approve to unblock.