stop testing Nim pre-1.6 in CI (#81)

* stop testing Nim pre-1.6 in CI

* simplify nimble file

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
             cpu: amd64
           #- os: windows
             #cpu: i386
-        branch: [version-1-2, version-1-4, version-1-6, devel]
+        branch: [version-1-6, devel]
         include:
           - target:
               os: linux

web3.nimble

@@ -6,7 +6,7 @@ description   = "This is the humble begginings of library similar to web3.[js|py
 license       = "MIT or Apache License 2.0"
 
 ### Dependencies
-requires "nim >= 1.2.0"
+requires "nim >= 1.6.0"
 requires "chronicles"
 requires "chronos"
 requires "eth"
@@ -22,16 +22,10 @@ proc test(args, path: string) =
   if not dirExists "build":
     mkDir "build"
 
-  let styleCheckStyle =
-    if (NimMajor, NimMinor) < (1, 6):
-      "hint"
-    else:
-      "error"
-
   exec "nim " & getEnv("TEST_LANG", "c") & " " & getEnv("NIMFLAGS") & " " & args &
     " --outdir:build -r --skipParentCfg" &
     " --warning[ObservableStores]:off --warning[GcUnsafe2]:off" &
-    " --styleCheck:usages --styleCheck:" & styleCheckStyle &
+    " --styleCheck:usages --styleCheck:error" &
     " --hint[XDeclaredButNotUsed]:off --hint[Processing]:off " &
     path