CI: rename julia-runtest branch (#263)

Author: timholy

.github/workflows/UnitTest.yml

@@ -43,7 +43,7 @@ jobs:
             ${{ runner.os }}-test-
             ${{ runner.os }}-
       - name: "Unit Test"
-        uses: julia-actions/julia-runtest@master
+        uses: julia-actions/julia-runtest@v1
 
       - uses: julia-actions/julia-processcoverage@v1
       - uses: codecov/codecov-action@v1