icedtea8_web: 1.6.2 -> 1.7.1

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/icedtea-web/versions.

These checks were done:

- built on NixOS
- ran `/nix/store/v9maiya65b10q73b3fb5zf02gqyn11jg-icedtea-web-1.7.1/bin/javaws --help` got 0 exit code
- ran `/nix/store/v9maiya65b10q73b3fb5zf02gqyn11jg-icedtea-web-1.7.1/bin/javaws help` got 0 exit code
- ran `/nix/store/v9maiya65b10q73b3fb5zf02gqyn11jg-icedtea-web-1.7.1/bin/javaws --version` and found version 1.7.1
- ran `/nix/store/v9maiya65b10q73b3fb5zf02gqyn11jg-icedtea-web-1.7.1/bin/javaws version` and found version 1.7.1
- ran `/nix/store/v9maiya65b10q73b3fb5zf02gqyn11jg-icedtea-web-1.7.1/bin/itweb-settings --help` got 0 exit code
- ran `/nix/store/v9maiya65b10q73b3fb5zf02gqyn11jg-icedtea-web-1.7.1/bin/itweb-settings help` got 0 exit code
- ran `/nix/store/v9maiya65b10q73b3fb5zf02gqyn11jg-icedtea-web-1.7.1/bin/policyeditor --help` got 0 exit code
- ran `/nix/store/v9maiya65b10q73b3fb5zf02gqyn11jg-icedtea-web-1.7.1/bin/policyeditor help` got 0 exit code
- found 1.7.1 with grep in /nix/store/v9maiya65b10q73b3fb5zf02gqyn11jg-icedtea-web-1.7.1
- directory tree listing: https://gist.github.com/0e5014eea224d7b6d3648167d610e4f0