switch chronos and asynctest to head; bump nim to 1.6.16

Author: gmega

ethers.nimble

@@ -3,9 +3,9 @@ author = "Nim Ethers Authors"
 description = "library for interacting with Ethereum"
 license = "MIT"
 
-requires "nim >= 1.6.0"
+requires "nim >= 1.6.16"
 requires "chronicles >= 0.10.3 & < 0.11.0"
-requires "chronos >= 3.0.0 & < 4.0.0"
+requires "chronos#head" # FIXME: change to >= 4.0.0 when chronos 4 is released
 requires "contractabi >= 0.6.0 & < 0.7.0"
 requires "questionable >= 0.10.2 & < 0.11.0"
 requires "upraises >= 0.1.0 & < 0.2.0"

testmodule/test.nimble

@@ -3,7 +3,7 @@ author = "Nim Ethers Authors"
 description = "Tests for Nim Ethers library"
 license = "MIT"
 
-requires "asynctest >= 0.4.0 & < 0.5.0"
+requires "asynctest#head" # FIXME change to 0.4.3 once we get a release
 requires "questionable >= 0.10.3 & < 0.11.0"
 
 task test, "Run the test suite":