Increasing guava version limit

[AUTplayed]

Hi, I ran all tests with guava versions 23 through 25 and they were all green
(except for failing.OptionalUnwrappedTest, which is on purpose? didn't work with v20 either, so it would explain the package name...)

This led me to the conclusion that it's save to increase the guava version limit.

This is important, because there is a security issue on versions 11.0 through 24.1.

Thanks

[cowtowncoder]

For what it is worth, security advisory is not relevant for Jackson, as far as I can see: problem is related to JDK serialization.
However, I have nothing against increasing range limit per se.

I think I will apply that against 2.10 branch, however; 3.0 is still quite far out.

[cowtowncoder]

Thank you for suggesting this: I merge this manually to be in 2.10, closing PR itself. WIll be in 2.10.0.