consolidate steps to avoid repeat installs

Author: JacksonBurns

.github/workflows/CI.yml

@@ -27,7 +27,7 @@ jobs:
 
       - name: Run tests
         run: |
-            julia -e 'using Pkg; Pkg.test("ReactionMechanismSimulator"; coverage=true)'
+            julia -e 'using Pkg; Pkg.develop(Pkg.PackageSpec(path="../ReactionMechanismSimulator.jl/")); Pkg.build("ReactionMechanismSimulator"); Pkg.test("ReactionMechanismSimulator"; coverage=true)'
 
       - uses: julia-actions/julia-processcoverage@v1