revert devmode

- didn't work
- almost completely reverts c94acdf2a9

README.rst

@@ -158,7 +158,7 @@ GitHub `releases page <https://github.com/iterative/dvc/releases>`_.
 
 .. code-block:: bash
 
-   snap install --devmode dvc_*.snap
+   snap install dvc_*.snap --dangerous --classic
 
 Package
 -------

snap/snapcraft.yaml

@@ -3,7 +3,7 @@ summary: Data Version Control
 description: Git for Data & Models https://dvc.org
 adopt-info: dvc
 grade: stable
-confinement: devmode
+confinement: classic  # for same reasons as snap `git-ubuntu`
 base: core18
 license: Apache-2.0
 plugs: