add check for Contao 4.5

[fritzmg]

This adds a separate check for Contao 4.5, which checks for PHP 7.1.0 and checks the ICU library version for at least 4.6.

[leofeyer]

To remain consistency, there should be only one red error message, not a red line and a grey line below.

[fritzmg]

To remain consistency, there should be only one red error message, not a red line and a grey line below.

But that is consistent.

[leofeyer]

Sorry, you are right. I did not recall correctly.

[fritzmg]

I have updated the PR. The Contao 4.5 check now inherits from the Contao 4 check.

[fritzmg]

@leofeyer what do you think, can this be merged?

[ausi]

@fritzmg we should probably update this check because since slug-generator version 1.0.2 the minimum ICU version is 4.2.1

[fritzmg]

Technically ICU 4.2.0 would still work though, wouldn't it? In that case composer would (in theory) only install 1.0.1 of ausi/slug-generator, since Contao allows ^1.0.1.

// oh nvm, the new requirement is lower not higher 😬