Setup mockk

[marcantoinefortier]

Fixes #1

[marcantoinefortier]

mockk library still not supporting iOS targets :

FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':shared:compileTestKotlinIosX64'.
> Could not resolve all files for configuration ':shared:iosX64TestCompileKlibraries'.
   > Could not resolve io.mockk:mockk:1.12.1.
     Required by:
         project :shared
      > No matching variant of io.mockk:mockk:1.12.1 was found. The consumer was configured to find a usage of 'kotlin-api' of a library, as well as attribute 'org.jetbrains.kotlin.platform.type' with value 'native', attribute 'org.jetbrains.kotlin.native.target' with value 'ios_x64' but:
          - Variant '-api' capability io.mockk:mockk:1.12.1 declares an API of a library:
              - Incompatible because this component declares a component, as well as attribute 'org.jetbrains.kotlin.platform.type' with value 'jvm' and the consumer needed a component, as well as attribute 'org.jetbrains.kotlin.platform.type' with value 'native'
              - Other compatible attribute:
                  - Doesn't say anything about org.jetbrains.kotlin.native.target (required 'ios_x64')
          - Variant '-runtime' capability io.mockk:mockk:1.12.1 declares a runtime of a library:
              - Incompatible because this component declares a component, as well as attribute 'org.jetbrains.kotlin.platform.type' with value 'jvm' and the consumer needed a component, as well as attribute 'org.jetbrains.kotlin.platform.type' with value 'native'
              - Other compatible attribute:
                  - Doesn't say anything about org.jetbrains.kotlin.native.target (required 'ios_x64')
* Try:
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BUILD FAILED in 18s