Added sql linter

Co-authored-by: Felix Delattre <fd@gfz-potsdam.de>

.gitlab-ci.yml

-image: python:3-buster
+image: python:3-bullseye
+
+linter:
+  before_script:
+    - pip3 install sqlfluff
+  script:
+    - sqlfluff lint --dialect postgres
 
 test:
   before_script:

migrations/00001_create-main-table.sql

 -- Create the `obm_buildings` table
-
-CREATE TABLE public.obm_buildings
-(
-    osm_id integer PRIMARY KEY
-);
-
-ALTER TABLE public.obm_buildings
-    OWNER to postgres;
+CREATE TABLE public.obm_buildings (osm_id integer PRIMARY KEY);
+ALTER TABLE public.obm_buildings OWNER TO postgres;

migrations/00003_add_column_geometry.sql

 ALTER TABLE public.obm_buildings
-    ADD COLUMN IF NOT EXISTS geometry geometry (Polygon, 4326);
+ADD COLUMN IF NOT EXISTS geometry GEOMETRY (Polygon, 4326);

migrations/00004_change_geometry_type.sql

+ALTER TABLE public.obm_buildings DROP COLUMN geometry;
 ALTER TABLE public.obm_buildings
-    DROP COLUMN geometry;
-ALTER TABLE public.obm_buildings
-    ADD COLUMN IF NOT EXISTS geometry geometry (GEOMETRY, 4326);
+ADD COLUMN IF NOT EXISTS geometry GEOMETRY (GEOMETRY, 4326);

migrations/00005_add_column_floorspace.sql

 ALTER TABLE public.obm_buildings
-    ADD COLUMN IF NOT EXISTS floorspace FLOAT;
+ADD COLUMN IF NOT EXISTS floorspace FLOAT;

migrations/00006_add_column_occupancy.sql

 ALTER TABLE public.obm_buildings
-    ADD COLUMN if NOT EXISTS occupancy TEXT;
+ADD COLUMN IF NOT EXISTS occupancy TEXT;