[libpeas] CI: fix CCACHE_* env vars values

[Jordan Petridis <jpetridis src gnome org>]

commit 6374d5719394d87a5e79993b045ee4956ec80c2a
Author: Jordan Petridis <jpetridis gnome org>
Date:   Tue Aug 6 20:33:40 2019 +0300

    CI: fix CCACHE_* env vars values
    
    Previously, the basedir env var didn't expand
    and the final value of the config looked like
    ${CI_PROJECT_DIR}/_ccache/ccache.conf as opposed to
    an actuall path.
    
    When gitlab parses the yml file, `CI_PROJECT_DIR` is a known
    value that can be expanded, while our custom variable for
    CCACHE_DIR isn't fully expanded due to pointing to a custom and
    thus ignored env var.
    
    Set the CCACHE_DIR to "$CI_PROJECT_DIR/_ccache" instead of
    CCACHE_BASEDIR to workaround this issue and have it properly expand.

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 8fe66ad..9170801 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -7,7 +7,7 @@ stages:
   stage: 'build'
   variables:
     CCACHE_BASEDIR: "${CI_PROJECT_DIR}"
-    CCACHE_DIR: "${CCACHE_BASEDIR}/_ccache"
+    CCACHE_DIR: "${CI_PROJECT_DIR}/_ccache"
     DEPS: >-
       gcc
       ccache