bump checkout, avoid redundant PR builds

.github/workflows/ci.yml

@@ -6,6 +6,10 @@ on:
   pull_request:
   workflow_dispatch:
 
+concurrency: # Cancel stale PR builds (but not push builds)
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
 jobs:
   build:
     strategy:
@@ -46,7 +50,7 @@ jobs:
     continue-on-error: ${{ matrix.branch == 'devel' }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           submodules: true
 

secp256k1.nimble

@@ -21,7 +21,7 @@ let styleCheckStyle = if (NimMajor, NimMinor) < (1, 6): "hint" else: "error"
 let cfg =
   " --styleCheck:usages --styleCheck:" & styleCheckStyle &
   (if verbose: "" else: " --verbosity:0 --hints:off") &
-  " --skipParentCfg --skipUserCfg"
+  " --skipParentCfg --skipUserCfg --outdir:build --nimcache:build/nimcache -f"
 
 proc build(args, path: string) =
   exec nimc & " " & lang & " " & cfg & " " & flags & " " & args & " " & path