Fix compiler version in `install.sh`

[erikrikarddaniel]

Unfortunately, I still couldn't build the container after you made a release. I think the problem was that if I didn't use --docker with the build command all worked because some other version of gcc was used.

Now, after explicitly depending on gcc >=4.7.0 in the meta.yaml file in the build recipe, the package builds with ioconda-utils build --packages sativa --docker --mulled-test pointing to my fork. With gcc versions from 10 and up, your version tests didn't work as expected, so I updated that.

When you have time, would you please check the PR and, when merged, make another release and I'll update the build scripts.