Made spring scope provided

[whiskeysierra]

Description

Motivation and Context

Fixes #194

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.

[whiskeysierra]

Each of the scopes (except for import) affects transitive dependencies in different ways, as is demonstrated in the table below. If a dependency is set to the scope in the left column, transitive dependencies of that dependency with the scope across the top row will result in a dependency in the main project with the scope listed at the intersection. If no scope is listed, it means the dependency will be omitted.

https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope

	compile	provided	runtime	test
compile	compile(*)	-	runtime	-
provided	provided	-	provided	-
runtime	runtime	-	runtime	-
test	test	-	test	-

On the other hand, optional should also work:

Marking dependencies as optional will not resolve them as transitive dependencies in the application which use your library (even if the scope is compile).

https://stackoverflow.com/a/5861855/232539

[whiskeysierra]

Somebody who depends on logbook-spring-boot-starter will use scope compile. The dependency to spring is now marked as provided and will in turn be omitted. Should solve the problem.