Merge branch 'develop-bump-what4-1.7'. Close #611.

**Description**

In order to keep Copilot effectively working in the current Haskell ecosystem,
as well as new versions of GHC, we need to extend the versions of dependencies
that Copilot can be installed with. The package `what4`  has seen release 1.7,
but we depend on versions prior to 1.7.

**Type**

- Management: update versions of dependencies.

**Additional context**

None.

**Requester**

- Ivan Perez.

**Method to check presence of bug**

Not applicable (not a bug).

**Expected result**

Copilot can be installed with the most recent version of  `what4` published on
hackage that do not require a change to the Haskell code.

The following Dockerfile installs copilot forcing the version of what4 to be
greater than or equal to 1.7, after which it prints the message "Success":

```Dockerfile
FROM ubuntu:focal

ENV DEBIAN_FRONTEND=noninteractive
RUN apt-get update

RUN apt-get install --yes \
      libz-dev \
      git \
      curl \
      gcc \
      g++ \
      make \
      libgmp3-dev  \
      pkg-config \
      z3

RUN mkdir -p $HOME/.ghcup/bin
RUN curl https://downloads.haskell.org/~ghcup/0.1.40.0/x86_64-linux-ghcup-0.1.40.0 -o $HOME/.ghcup/bin/ghcup
RUN chmod a+x $HOME/.ghcup/bin/ghcup
ENV PATH=$PATH:/root/.ghcup/bin/
ENV PATH=$PATH:/root/.cabal/bin/

SHELL ["/bin/bash", "-c"]

RUN ghcup install ghc 9.10.1
RUN ghcup install cabal 3.2
RUN ghcup set ghc 9.10.1
RUN cabal update

SHELL ["/bin/bash", "-c"]
CMD git clone $REPO && cd $NAME && git checkout $COMMIT && cd .. \
  && cabal v1-sandbox init \
  && cabal v1-install alex happy --constraint='happy <= 2' \
  && cabal v1-install --constraint='what4 >= 1.7' \
                      $NAME/copilot/ \
                      $NAME/copilot-c99/ \
                      $NAME/copilot-core/ \
                      $NAME/copilot-prettyprinter/ \
                      $NAME/copilot-interpreter/ \
                      $NAME/copilot-language/ \
                      $NAME/copilot-libraries/ \
                      $NAME/copilot-theorem/ \
  && echo "Success"
```

Command (substitute variables based on new path after merge):
```
$ docker run -e "REPO=https://github.com/Copilot-Language/copilot" -e "NAME=copilot" -e "COMMIT=<HASH>" -it copilot-verify-611
```

**Solution implemented**

Bump version bounds on `what4`.

**Further notes**

None.

Author: ivanperez-keera

copilot-theorem/CHANGELOG

@@ -1,5 +1,6 @@
-2025-05-29
+2025-07-05
         * Removed unused pragmas. (#613)
+        * Relax version constraint on what4. (#611)
 
 2025-05-07
         * Version bump (4.4). (#618)

copilot-theorem/copilot-theorem.cabal

@@ -61,7 +61,7 @@ library
                           , random                >= 1.1 && < 1.3
                           , transformers          >= 0.5 && < 0.7
                           , xml                   >= 1.3 && < 1.4
-                          , what4                 >= 1.3 && < 1.7
+                          , what4                 >= 1.3 && < 1.8
 
                           , copilot-core          >= 4.4 && < 4.5
                           , copilot-prettyprinter >= 4.4 && < 4.5