Upgrade project deps to latest; use semver, not wildcard nor tilde

[jpschorr]

• Upgrade project deps to latest
• use semver, not wildcard nor tilde requirements (see https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html)
• upgrade deny.toml to remove deprecated specifications (see Add version = 2 EmbarkStudios/cargo-deny#611)
• update CI nightly rust for dependency upgrades

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.49%. Comparing base (83efb7f) to head (fdd7148).
Report is 1 commits behind head on dev-ion-doc.

Additional details and impacted files

@@             Coverage Diff              @@
##           dev-ion-doc     #494   +/-   ##
============================================
  Coverage        80.49%   80.49%           
============================================
  Files               73       73           
  Lines            18947    18947           
  Branches         18947    18947           
============================================
  Hits             15251    15251           
  Misses            3271     3271           
  Partials           425      425           

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[github-actions]

Conformance comparison report

	Base (83efb7f)	63c2324	+/-
% Passing	90.35%	90.35%	0.00%
✅ Passing	5731	5731	0
❌ Failing	612	612	0
🔶 Ignored	0	0	0
Total Tests	6343	6343	0

Number passing in both: 5731

Number failing in both: 612

Number passing in Base (83efb7f) but now fail: 0

Number failing in Base (83efb7f) but now pass: 0