Add migration instructions for Meteor 3

[perbergland]

Add a deprecation notice to the readme and instructions on how to migrate the code to Meteor 3 and its Express-based webapp

[github-actions[bot]]

Thank you for submitting this issue!

We, the Members of Meteor Community Packages take every issue seriously. Our goal is to provide long-term lifecycles for packages and keep up with the newest changes in Meteor and the overall NodeJs/JavaScript ecosystem.

However, we contribute to these packages mostly in our free time. Therefore, we can't guarantee your issues to be solved within certain time.

If you think this issue is trivial to solve, don't hesitate to submit a pull request, too! We will accompany you in the process with reviews and hints on how to get development set up.

Please also consider sponsoring the maintainers of the package. If you don't know who is currently maintaining this package, just leave a comment and we'll let you know

[StorytellerCZ]

Added initial deprecation notice. Will release deprecated version 1.2.0 to draw more attention to this and then as I migrate my app will add a migration guide.

[matheusccastroo]

~~@perbergland @StorytellerCZ Not sure I understood why it needs to be deprecated.~~

~~This package creates a router that enables to pass params through the url and have some additional fancy stuff with filters etc. Does express have a direct mapping with those features?~~

Taking a look here, seems that express have the req.params for the url named parameters and also the filter is actually simple to implement too. Gotcha, now makes more sense 😄