CRAN release wooldridge v1.4-7

wooldridge 1.4-7

• Re-compiled package documentation (.Rd files) via roxygen2 to properly apply the textbook URL fixes implemented in 1.4-6.

wooldridge 1.4-6

• Fixed broken Cengage textbook URLs in package documentation that were causing redirect limit errors during CRAN checks in issue #16.

wooldridge 1.4-5

• Updated maintainer email address.
• Migrated continuous integration from Travis CI and AppVeyor to modern GitHub Actions.
• Fixed broken build and CRAN status badges in the README.md.

wooldridge 1.4-4

Clear NOTEs on "Lost braces" from documentation.