Parse repo in pacman output (#766)

Adds GitLab + Docker-based pacman test environment. Refs #561.

.gitlab-ci.yml

@@ -0,0 +1,8 @@
+pacman:
+  image: archlinux
+  script:
+    - pacman -Sy --noconfirm python-pip
+    - python -m pip install poetry
+    - poetry install
+    - python -m pip install .
+    - mpm --pacman -v DEBUG install vim

meta_package_manager/managers/pacman.py

@@ -131,11 +131,11 @@ def search(self, query: str, extended: bool, exact: bool) -> Iterator[Package]:
         output = self.run_cli("--sync", "--search", query)
 
         regexp = re.compile(
-            r"(?P<package_id>\S+)\s+(?P<version>\S+).*\n\s+(?P<description>.+)",
+            r"(?P<repo_id>\S+?)/(?P<package_id>\S+)\s+(?P<version>\S+).*\n\s+(?P<description>.+)",
             re.MULTILINE | re.VERBOSE,
         )
 
-        for package_id, version, description in regexp.findall(output):
+        for repo_id, package_id, version, description in regexp.findall(output):
             yield self.package(
                 id=package_id,
                 description=description,