Update several dependencies, loosen patch requirements

[ebkalderon]

Changed

• Update httparse dependency from 1.3.5 to 1.8 (also relaxing semver requirement).
• Update memchr dependency from 2.4.1 to 2.5 (also relaxing semver requirement).
• Relax version requirement for tower dependency from 0.4.12 to 0.4.
• Relax version requirement for tracing dependency from 0.1.34 to 0.1.
• Update async-tungstenite dev dependency from 0.17 to 0.18.
• Relax version requirement for tracing-subscriber dev dependency from 0.3.11 to 0.3.
• Update ws_stream_tungstenite dev dependency from 0.8 to 0.9.

Closes #357.
Closes #360.
Relates to #359, #362.