fix(common): revert MSRV to 1.49

[TommyCpp]

• remove const generic in order_map
• replace ishac with hyper in zipkin's doc example. ishac currently has a dependency that requires 1.54 MSRV
• Update CI

[codecov]

Codecov Report

Merging #827 (d70f6f4) into main (b5c3ec6) will increase coverage by 0.0%.
The diff coverage is n/a.

@@          Coverage Diff          @@
##            main    #827   +/-   ##
=====================================
  Coverage   69.8%   69.8%           
=====================================
  Files        111     111           
  Lines       9196    9196           
=====================================
+ Hits        6421    6427    +6     
+ Misses      2775    2769    -6     

Impacted Files	Coverage Δ
opentelemetry-api/src/lib.rs	100.0% <ø> (ø)
opentelemetry-api/src/trace/order_map.rs	64.2% <ø> (ø)
opentelemetry-jaeger/src/lib.rs	92.5% <ø> (ø)
opentelemetry-zipkin/src/lib.rs	100.0% <ø> (ø)
opentelemetry/src/lib.rs	100.0% <ø> (ø)
opentelemetry-jaeger/src/exporter/mod.rs	54.0% <0.0%> (+3.0%)	⬆️

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