Add mojo-http2 0.2.8

[nsalerni]

Adds mojo-http2 0.2.8, HPACK and HTTP/2 with h2c and TLS transports.

This is a follow-up to #317. That PR bundled five packages plus build-order changes; this one adds only mojo-http2.

mojo-net 0.2.6 and mojo-tls 0.3.2 are now on the channel for linux-64, linux-aarch64, and osx-arm64, so this recipe can resolve its sibling deps.

Version	0.2.8
Source	https://github.com/nsalerni/mojo-http2/tree/v0.2.8
Pin	c8038269dfef544a7325a971857803b3bfc5b725
Artifacts	hpack.mojoc and h2.mojoc via mojo precompile
Sibling deps	mojo-net >=0.2.4,<0.3.0 (0.2.6 published), mojo-tls >=0.2.0,<0.4.0 (0.3.2 published)

Checklist

• Recipe specifies compatible MAX/Mojo (mojo-compiler >=1.0.0,<1.1.0)
• License file is packaged (license_file: LICENSE)
• Build number set to 0 (new package)
• N/A: bump build number

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