chore(dependencies): Update versions to use PF6

[adamviktora]

Closes #55

Few things / concerns:

1. yarn lint:md was failing with the previous configuration in .eslintrc-md.json so I updated that to only run on js / jsx /ts / tsx blocks inside the markdown files. But I am not sure it works correctly + I don't know if the intention of running lint on .md files is to only check blocks of React code, or check the whole file.
2. Current version of @patternfly/documentation-framework (6.0.0-alpha.77) is using old peer dependencies of @patternfly/patternfly, /react-core, /react-table and /react-code-editor. So versions of these packages are intentionally set to the ones specified in documentation-framework. We should update the versions of these packages again once beta is released.
3. I updated the yarn.lock file based on a generated yarn.lock gotten from running the updated patternfly-extension-seed on a new repo (npx tmplr adamviktora/patternfly-extension-seed and then yarn install), I assume this is the way to do so - if not, let me know.

[wise-king-sullyman]

yarn lint:md was failing with the previous configuration in .eslintrc-md.json so I updated that to only run on js / jsx /ts / tsx blocks inside the markdown files. But I am not sure it works correctly + I don't know if the intention of running lint on .md files is to only check blocks of React code, or check the whole file.

It seems like this isn't catching any lint issues when I introduce them in the markdown....but it seems like it doesn't work properly now either so I won't block this PR over it.

Current version of @patternfly/documentation-framework (6.0.0-alpha.77) is using old peer dependencies of @patternfly/patternfly, /react-core, /react-table and /react-code-editor. So versions of these packages are intentionally set to the ones specified in documentation-framework. We should update the versions of these packages again once beta is released.

Makes sense, though I do think we should probably leave this issue open until we're either able to update to the beta versions or we reach a final decision about not having a beta version.

I updated the yarn.lock file based on a generated yarn.lock gotten from running the updated patternfly-extension-seed on a new repo (npx tmplr adamviktora/patternfly-extension-seed and then yarn install), I assume this is the way to do so - if not, let me know.

Yep that works! Though if you're working on this repo in the future we actually have a convenience script devSetup.sh which executes the seed in the seed repo with a set of predefined values for stuff like this.

[wise-king-sullyman]

I'm going to merge this PR but disconnect #53 so that it stays open for now.