Add gosec linter (#1342)

This PR adds `gosec` linter with the following checks disabled:

- G102: Bind to all interfaces
- G107: Url provided to HTTP request as taint input
- G112: Potential slowloris attack
- G114: Use of net/http serve function that has no support for setting timeouts
- G204: Audit use of command execution
- G401: Detect the usage of DES, RC4, MD5 or SHA1
- G402: Look for bad TLS connection settings
- G404: Insecure random number source (rand)
- G501: Import blocklist: crypto/md5
- G505: Import blocklist: crypto/sha1

We have complaints related to the checks above. They have to be addressed separately.

iface/tun_linux.go

@@ -99,7 +99,8 @@ func (c *tunDevice) assignAddr() error {
 	}
 	if len(list) > 0 {
 		for _, a := range list {
-			err = netlink.AddrDel(link, &a)
+			addr := a
+			err = netlink.AddrDel(link, &addr)
 			if err != nil {
 				return err
 			}