add ability to drop incoming headers #108

In some cases proxy should sanitize incoming headers. --drop-header and $DROP_HEADERS set list of headers (keys) and those headers removed from the request.

.github/workflows/ci.yml

@@ -11,10 +11,10 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - name: set up go 1.16
+      - name: set up go 1.17
         uses: actions/setup-go@v2
         with:
-          go-version: 1.16
+          go-version: 1.17
         id: go
 
       - name: checkout