Fix tests on Nim 1.6.12

Ignore the nimble.lock at the root level when running tests

testmodules/chronos/test.nimble

@@ -6,4 +6,4 @@ license = "MIT"
 requires "chronos"
 
 task test, "Runs the test suite":
-  exec "nim c -f -r test.nim"
+  exec "nim c -f -r --skipParentCfg test.nim"

testmodules/stdlib/test.nimble

@@ -4,4 +4,4 @@ description = "Asynctest tests for std/unittest and std/asyncdispatch"
 license = "MIT"
 
 task test, "Runs the test suite":
-  exec "nim c -f -r test.nim"
+  exec "nim c -f -r --skipParentCfg test.nim"

testmodules/unittest2/test.nimble

@@ -7,4 +7,4 @@ requires "unittest2"
 requires "chronos"
 
 task test, "Runs the test suite":
-  exec "nim c -f -r test.nim"
+  exec "nim c -f -r --skipParentCfg test.nim"