update coverage to use c8 for esm

Makefile

@@ -60,7 +60,7 @@ test: ## run tests
 test: node_modules out
 	yarn mocha $(MOCHA_ARGS) "out/**/Test*.js"
 
-NYC_ARGS := --all \
+COVER_ARGS := --all \
 	--check-coverage \
 	--exclude ".eslintrc.js" \
 	--exclude "bundle/**" \
@@ -75,7 +75,7 @@ NYC_ARGS := --all \
 
 cover: ## run tests with coverage
 cover: node_modules out
-	yarn nyc $(NYC_ARGS) yarn mocha $(MOCHA_ARGS) "out/**/Test*.js"
+	yarn c8 $(COVER_ARGS) yarn mocha $(MOCHA_ARGS) "out/**/Test*.js"
 
 # from https://marmelab.com/blog/2016/02/29/auto-documented-makefile.html
 help: ## print this help

README.md

@@ -92,7 +92,7 @@ found:
 
 ```none
   5) example properties
-       some IDs
+       some UUIDs
          should be a good one:
      Error: Property failed by returning false after 3 runs and 8 shrinks, failing on: "00000000-a000-300d-8000-000000000000" (seed: -886543855, path: '2:0:10:0:10:0:2:3:3')
       at /home/ssube/code/ssube/mocha-foam/out/src/index.js:20:385

package.json

@@ -17,16 +17,16 @@
   ],
   "devDependencies": {
     "@types/chai-as-promised": "7.1.4",
-    "@types/mocha": "8.2.3",
-    "@types/node": "16.4.0",
+    "@types/mocha": "9.0.0",
+    "@types/node": "16.4.2",
     "@types/sinon": "10.0.2",
     "@types/sinon-chai": "3.2.5",
+    "c8": "^7.7.3",
     "chai": "4.3.4",
     "chai-as-promised": "7.1.1",
     "esm": "3.2.25",
     "fast-check": "2.17.0",
     "mocha": "9.0.3",
-    "nyc": "15.1.0",
     "sinon": "11.1.1",
     "sinon-chai": "3.7.0",
     "source-map-support": "0.5.19",