Allow v0.3 to read v0.2 instance files

test/validation/repair_test.jl

@@ -4,11 +4,9 @@
 
 using UnitCommitment, JSON, GZip, DataStructures
 
-basedir = @__DIR__
-
 function parse_case14()
     return JSON.parse(
-        GZip.gzopen("$basedir/../../instances/test/case14.json.gz"),
+        GZip.gzopen("$FIXTURES/case14.json.gz"),
         dicttype = () -> DefaultOrderedDict(nothing),
     )
 end