Enable git submodules cloning when using go-git

Signed-off-by: Stefan Prodan <[email protected]>

Author: stefanprodan

docs/spec/v1beta1/gitrepositories.md

@@ -194,10 +194,10 @@ and also impact the traffic costs.
 To be able to support Azure DevOps a compromise solution was built, giving the user the
 option to select the git library while accepting the drawbacks.
 
-| Git Implementation | Shallow Clones | V2 Protocol Support |
-|---|---|---|
-| 'go-git' | true | false |
-| 'libgit2' | false | true |
+| Git Implementation | Shallow Clones | Git Submodules | V2 Protocol Support |
+|---|---|---|---|
+| 'go-git' | true | true | false |
+| 'libgit2' | false | false | true |
 
 Pull the master branch from a repository in Azure DevOps.
 
@@ -318,7 +318,7 @@ data:
   password: <BASE64>
 ```
 
-## HTTPS self-signed certificates
+### HTTPS self-signed certificates
 
 Cloning over HTTPS from a Git repository with a self-signed certificate:
 

pkg/git/gogit/checkout.go

@@ -67,7 +67,7 @@ func (c *CheckoutBranch) Checkout(ctx context.Context, path, url string, auth *g
 		SingleBranch:      true,
 		NoCheckout:        false,
 		Depth:             1,
-		RecurseSubmodules: 0,
+		RecurseSubmodules: extgogit.DefaultSubmoduleRecursionDepth,
 		Progress:          nil,
 		Tags:              extgogit.NoTags,
 		CABundle:          auth.CABundle,
@@ -99,7 +99,7 @@ func (c *CheckoutTag) Checkout(ctx context.Context, path, url string, auth *git.
 		SingleBranch:      true,
 		NoCheckout:        false,
 		Depth:             1,
-		RecurseSubmodules: 0,
+		RecurseSubmodules: extgogit.DefaultSubmoduleRecursionDepth,
 		Progress:          nil,
 		Tags:              extgogit.NoTags,
 		CABundle:          auth.CABundle,
@@ -131,7 +131,7 @@ func (c *CheckoutCommit) Checkout(ctx context.Context, path, url string, auth *g
 		ReferenceName:     plumbing.NewBranchReferenceName(c.branch),
 		SingleBranch:      true,
 		NoCheckout:        false,
-		RecurseSubmodules: 0,
+		RecurseSubmodules: extgogit.DefaultSubmoduleRecursionDepth,
 		Progress:          nil,
 		Tags:              extgogit.NoTags,
 		CABundle:          auth.CABundle,
@@ -173,7 +173,7 @@ func (c *CheckoutSemVer) Checkout(ctx context.Context, path, url string, auth *g
 		RemoteName:        git.DefaultOrigin,
 		NoCheckout:        false,
 		Depth:             1,
-		RecurseSubmodules: 0,
+		RecurseSubmodules: extgogit.DefaultSubmoduleRecursionDepth,
 		Progress:          nil,
 		Tags:              extgogit.AllTags,
 		CABundle:          auth.CABundle,