use latest micromamba and fix MAMBA_ROOT_PREFIX

repo2docker/buildpacks/conda/__init__.py

@@ -55,6 +55,7 @@ class CondaBuildPack(BaseImage):
             ("NPM_DIR", "${APP_BASE}/npm"),
             ("NPM_CONFIG_GLOBALCONFIG", "${NPM_DIR}/npmrc"),
             ("NB_ENVIRONMENT_FILE", self._nb_environment_file),
+            ("MAMBA_ROOT_PREFIX", "${CONDA_DIR}"),
         ]
         if self._nb_requirements_file:
             env.append(("NB_REQUIREMENTS_FILE", self._nb_requirements_file))

repo2docker/buildpacks/conda/install-base-env.bash

@@ -6,7 +6,7 @@ set -ex
 
 cd $(dirname $0)
 
-URL="https://micro.mamba.pm/api/micromamba/linux-64/latest"
+URL="https://anaconda.org/conda-forge/micromamba/0.13.1/download/linux-64/micromamba-0.13.1-0.tar.bz2"
 
 # make sure we don't do anything funky with user's $HOME
 # since this is run as root

tests/conda/binder-dir/verify

@@ -5,6 +5,6 @@ from subprocess import check_output
 assert sys.version_info[:2] == (3, 5), sys.version
 
 out = check_output(["/tmp/bin/micromamba", "--version"]).decode("utf8").strip()
-assert out == "0.13.0", out
+assert out == "0.13.1", out
 
 import numpy