IPM update dependency version conflict

[isc-jlechtne]

Describe the bug

Found an issue with update when the dependencies of the base module also get updated. Issue found when updating a module from 2.0.0 to 2.1.0. A dependency in 2.1.0 gets bumped to 6.2.0+snapshot while 2.0.0 requires ^5.4.1. Trying to perform this update encountered the following error:

Requested version (dependency 6.2.0+snapshot) does not satisfy the requirements of other modules installed in the current namespace (dependency: ^5.4.1).

To Reproduce

Steps to reproduce the behavior:

1. Have modules A, B, & C. Module A depends on B which in turn depends on C
2. Pre update versions:

• Module A: 2.0.0, requires B 1.0.0
• Module B: 1.0.0, requires C ^5.4.1
• Module C: 5.6.45+snapshot

3. Post update versions

• Module A: 2.1.0+snapshot, requires B ^2.0.0
• Module B: 2.0.0+snapshot, requires C ^6.1.15
• Module C: 6.2.0+snapshot

4. Run zpm "install <Module A> 2.0.0"
5. Run zpm "update <Module A> 2.1.0+snapshot" (this should error)

Expected behavior

Expected behavior is for Module A and all of its dependencies to successfully update as the post-update versions do satisfy requirements.

[isc-dchui]

Sounds related to #430.