aws-sam-cli: update requests dependency to 2.22.0

[scoates]

Motivation for this change

pythonPackages.requests was updated to v2.22.0 on July 21.

aws-sam-cli is hard-coded to set the requests version to 2.21.0, so aws-sam-cli currently fails to build.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nix-review --run "nix-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

Notify maintainers

cc @andreabedini @dhl

[grahamc]

@GrahamcOfBorg build aws-sam-cli

[jonringer]

nix-review passes on NixOS
diff LGTM
executable seems to work
leaf package

[2 built, 15 copied (4.4 MiB), 1.0 MiB DL]
https://github.com/NixOS/nixpkgs/pull/67267
1 package were build:
aws-sam-cli