fix: remove use of margin auto for layout where it breaks in ie11 (#182)

src/profile/components/__snapshots__/ProfilePage.test.jsx.snap

@@ -2052,7 +2052,7 @@ exports[`<ProfilePage /> Renders correctly in various states while saving an edi
                     </span>
                   </div>
                   <div
-                    className="form-group flex-shrink-0 mr-auto"
+                    className="form-group flex-shrink-0 flex-grow-1"
                   >
                     <button
                       aria-disabled={false}

src/profile/components/forms/elements/FormControls.jsx

@@ -28,7 +28,7 @@ function FormControls({
           onChange={changeHandler}
         />
       </div>
-      <div className="form-group flex-shrink-0 mr-auto">
+      <div className="form-group flex-shrink-0 flex-grow-1">
         <StatefulButton
           type="submit"
           className="btn-primary"