Upgrade dependencies, Send + Sync

[mappum]

This PR upgrades dependencies, and makes the Merk type Send and Sync for easier async compatibility.

[codecov]

Codecov Report

Attention: Patch coverage is 84.61538% with 6 lines in your changes missing coverage. Please review.

Project coverage is 94.07%. Comparing base (088e2bb) to head (62d6214).
Report is 15 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/merk/mod.rs	88.88%	2 Missing ⚠️
src/merk/snapshot.rs	84.61%	2 Missing ⚠️
src/tree/debug.rs	0.00%	1 Missing ⚠️
src/tree/mod.rs	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop      #78      +/-   ##
===========================================
+ Coverage    92.00%   94.07%   +2.06%     
===========================================
  Files           28       27       -1     
  Lines         5480     5449      -31     
===========================================
+ Hits          5042     5126      +84     
+ Misses         438      323     -115     

Files with missing lines	Coverage Δ
src/merk/chunks.rs	99.64% <ø> (-0.02%)	⬇️
src/merk/restore.rs	97.08% <ø> (-0.02%)	⬇️
src/proofs/chunk.rs	96.69% <100.00%> (-0.09%)	⬇️
src/proofs/query/map.rs	98.83% <100.00%> (+0.17%)	⬆️
src/proofs/query/mod.rs	99.02% <100.00%> (-0.03%)	⬇️
src/proofs/tree.rs	94.21% <ø> (+0.85%)	⬆️
src/test_utils/crash_merk.rs	74.46% <ø> (+1.55%)	⬆️
src/test_utils/mod.rs	84.42% <100.00%> (+22.02%)	⬆️
src/tree/fuzz_tests.rs	100.00% <ø> (ø)
src/tree/link.rs	93.97% <ø> (-0.17%)	⬇️
... and 7 more

... and 7 files with indirect coverage changes