Fix Go packages when using Go modules (#351)

src/executor.rs

@@ -101,6 +101,21 @@ impl Executor {
         self
     }
 
+    /// See `std::process::Command::remove_env`
+    pub fn env_remove<K>(&mut self, key: K) -> &mut Executor
+    where
+        K: AsRef<OsStr>,
+    {
+        match self {
+            Executor::Wet(c) => {
+                c.env_remove(key);
+            }
+            Executor::Dry(_) => (),
+        }
+
+        self
+    }
+
     #[allow(dead_code)]
     /// See `std::process::Command::env`
     pub fn env<K, V>(&mut self, key: K, val: V) -> &mut Executor

src/steps/generic.rs

@@ -36,7 +36,11 @@ pub fn run_go(base_dirs: &BaseDirs, run_type: RunType) -> Result<()> {
         .require()?;
 
     print_separator("Go");
-    run_type.execute(&go).arg("get").arg("-u").arg("all").check_run()
+    run_type
+        .execute(&go)
+        .args(&["get", "-u", "all"])
+        .env_remove("GO111MODLE")
+        .check_run()
 }
 
 pub fn run_gem(base_dirs: &BaseDirs, run_type: RunType) -> Result<()> {