Bump github.com/hashicorp/go-retryablehttp from 0.6.4 to 0.6.8

Bumps [github.com/hashicorp/go-retryablehttp](https://github.com/hashicorp/go-retryablehttp) from 0.6.4 to 0.6.8.
- [Release notes](https://github.com/hashicorp/go-retryablehttp/releases)
- [Commits](hashicorp/go-retryablehttp@v0.6.4...v0.6.8)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

go.mod

@@ -3,7 +3,7 @@ module github.com/gitlabhq/terraform-provider-gitlab
 go 1.15
 
 require (
-	github.com/hashicorp/go-retryablehttp v0.6.4
+	github.com/hashicorp/go-retryablehttp v0.6.8
 	github.com/hashicorp/terraform-plugin-sdk v1.15.0
 	github.com/mitchellh/hashstructure v1.0.0
 	github.com/xanzy/go-gitlab v0.44.0

go.sum

@@ -97,6 +97,8 @@ github.com/hashicorp/go-plugin v1.2.0 h1:CUfYokW0EJNDcGecVrHZK//Cp1GFlHwoqtcUIEi
 github.com/hashicorp/go-plugin v1.2.0/go.mod h1:F9eH4LrE/ZsRdbwhfjs9k9HoDUwAHnYtXdgmf1AVNs0=
 github.com/hashicorp/go-retryablehttp v0.6.4 h1:BbgctKO892xEyOXnGiaAwIoSq1QZ/SS4AhjoAh9DnfY=
 github.com/hashicorp/go-retryablehttp v0.6.4/go.mod h1:vAew36LZh98gCBJNLH42IQ1ER/9wtLZZ8meHqQvEYWY=
+github.com/hashicorp/go-retryablehttp v0.6.8 h1:92lWxgpa+fF3FozM4B3UZtHZMJX8T5XT+TFdCxsPyWs=
+github.com/hashicorp/go-retryablehttp v0.6.8/go.mod h1:vAew36LZh98gCBJNLH42IQ1ER/9wtLZZ8meHqQvEYWY=
 github.com/hashicorp/go-safetemp v1.0.0 h1:2HR189eFNrjHQyENnQMMpCiBAsRxzbTMIgBhEyExpmo=
 github.com/hashicorp/go-safetemp v1.0.0/go.mod h1:oaerMy3BhqiTbVye6QuFhFtIceqFoDHxNAB65b+Rj1I=
 github.com/hashicorp/go-uuid v1.0.0/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=