Fix HTTP/2 feature check

[Ndiritu]

related to #854

Before enabling HTTP/2, we check if the feature is supported by curl. curl_version()["features"] provides a bitmask comprised of the supported features.

We perform a bitwise & with the CURL_VERSION_HTTP2 flag to check if it's enabled.

Previous implementation had 2 bugs:

• We should be comparing the result of the bitwise operation with the CURL_VERSION_HTTP2 flag
• Without parentheses, curl_version()["features"] & CURL_VERSION_HTTP2 !== 0 first evaluates CURL_VERSION_HTTP2 !== 0 then performs the bitwise & always returning 1 hence HTTP/2 would always be enabled even if the curl library doesn't enable it.

This PR fixes this.

Microsoft Reviewers: Open in CodeFlow