Relaxing bounds: `padic` builds with newer versions of ghc, integer-gmp, constraints works

Build report:

the project builds with ghc-9.12.2, and works fine

test passes

bench passes after removing the not existing functions and modules

the bounds on base, integer-gmp, constraints can be relaxed to:

```
base >= 4.14 && < 4.22
constraints >= 0.13 && < 0.15
integer-gmp >= 1.0.3 && < 1.2
```