tests.yml: Move environment variables to top level env block.

Unfortunately GitHub actions do not support building one variable from another
in this block, so the values are fully defined.

Signed-off-by: Chris PeBenito <chpebeni@linux.microsoft.com>

.github/workflows/tests.yml

@@ -3,8 +3,21 @@ name: Build tests
 on: [push, pull_request]
 
 env:
+  # This should be the minimum version required to run setools:
   SELINUX_USERSPACE_VERSION: 3.2
 
+  # GitHub doesn't support building env
+  # vars from others in this block.
+  USERSPACE_SRC: /tmp/selinux-src
+  #SEPOL_SRC: ${USERSPACE_SRC}/libsepol
+  SEPOL_SRC: /tmp/selinux-src/libsepol
+  #LIBSEPOLA: ${SEPOL_SRC}/src/libsepol.a
+  LIBSEPOLA: /tmp/selinux-src/libsepol/src/libsepol.a
+  #SELINUX_SRC: ${USERSPACE_SRC}/libselinux
+  SELINUX_SRC: /tmp/selinux-src/libselinux
+  #CHECKPOLICY_SRC: ${USERSPACE_SRC}/checkpolicy
+  CHECKPOLICY_SRC: /tmp/selinux-src/checkpolicy
+
 jobs:
   build:
     runs-on: ubuntu-20.04
@@ -49,17 +62,6 @@ jobs:
         sudo python -m pip install -U \
             tox
 
-    - name: Configure environment
-      run: |
-        USERSPACE_SRC=/tmp/selinux-src
-        SEPOL_SRC=${USERSPACE_SRC}/libsepol
-        LIBSEPOLA=${SEPOL_SRC}/src/libsepol.a
-        echo "USERSPACE_SRC=$USERSPACE_SRC" >> $GITHUB_ENV
-        echo "SEPOL_SRC=${SEPOL_SRC}" >> $GITHUB_ENV
-        echo "LIBSEPOLA=${LIBSEPOLA}" >> $GITHUB_ENV
-        echo "SELINUX_SRC=${USERSPACE_SRC}/libselinux" >> $GITHUB_ENV
-        echo "CHECKPOLICY_SRC=${USERSPACE_SRC}/checkpolicy" >> $GITHUB_ENV
-
     - name: Build toolchain
       run: |
         # Download current SELinux userspace tools and libraries