Update Golang 1.13.6

full diff: https://github.com/golang/go/compare/go1.13.5...go1.13.6

go1.13.6 (released 2020/01/09) includes fixes to the runtime and the net/http
package. See the Go 1.13.6 milestone on the issue tracker for details.

https://github.com/golang/go/issues?q=milestone%3AGo1.13.6+label%3ACherryPickApproved

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

.github/workflows/nightly.yml

@@ -12,7 +12,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v1
         with:
-          go-version: '1.13.5'
+          go-version: '1.13.6'
 
       - name: Checkout
         uses: actions/checkout@v1
@@ -123,7 +123,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v1
         with:
-          go-version: '1.13.5'
+          go-version: '1.13.6'
 
       - name: Checkout
         uses: actions/checkout@v1