Upgrades to ecoCopula

[fontikar]

Creating this issue so I can tag my commits and refer to this issue. I will work off a seperate branch for each of these features :)

• [x] Upgrade to testhat 3
• [ ] Breakdown fixtures into seperate .rds? https://r-pkgs.org/testing-design.html#storing-test-data
• [x] Expand testing suite
• [x] Use of GitHub Actions for continuous integration and deployment (Travis has been superseded)
• [ ] Nice hex sticker - @gordy2x do you have any preferences or ideas? Can be a nice plot or diagram
• [ ] Landing page website to host documentation

[fontikar]

Lazy data loading for spider dataset