Added a flag to force kiwix build to not do fast_clone

- Docopt cannot do fast_clone cause it is getting a
    specific commit id. This will be changed when a new
    release is available.

kiwixbuild/dependencies/docoptcpp.py

@@ -13,6 +13,7 @@ class docoptcpp(Dependency):
     class Source(GitClone):
         git_remote = "https://github.com/docopt/docopt.cpp.git"
         git_dir = "docopt.cpp"
+        force_full_clone = True
         git_ref = "3dd23e3280f213bacefdf5fcb04857bf52e90917"
 
     class Builder(CMakeBuilder):