feat: make internal repo fields public for ease of use.

That way, functions or methods taking such a type as argument
have access to the underlying repository so it doesn't need
to be passed as separate argument.

Author: Byron

gix/src/filter.rs

@@ -70,7 +70,8 @@ pub mod pipeline {
 pub struct Pipeline<'repo> {
     inner: gix_filter::Pipeline,
     cache: gix_worktree::Stack,
-    repo: &'repo Repository,
+    /// The repository this pipeline is associated with.
+    pub repo: &'repo Repository,
 }
 
 /// Lifecycle