test: fix the hash for node 12.18.3

.npmrc

@@ -1,8 +1,12 @@
+# updating this changes the target Node version used by this package
+# make sure to update the CI versions if you changed this
+# also make sure to update the hash files in script/fixtures/SHASUM256.txt
 target=v12.18.3
+
 node-version=12.18.3
 public-hoist-pattern[]=*
 package-lock=false
 lockfile=true
 prefer-frozen-lockfile=true
 child-concurrency=1 # node-gyp fails on windows
-strict-peer-dependencies=false
+strict-peer-dependencies=false

spec/fixtures/SHASUMS256.txt

@@ -1,4 +1,4 @@
-f2777bf2b140033c01d5f912df510dfa394e748f92bbaed24c832abf36cb3bdf ./node-v10.20.1-headers.tar.gz
-ea39a70b715bfbd0281979c95a5b81136ffdc0e5bf66b1fd7dc3ef3473ce2c5a ./node-v10.20.1.tar.gz
+164edc71e46cf86ac5d9fcac00dc69c09bb09614b767c4c775aa7747b42e8188 ./node-v12.18.3-headers.tar.gz
+6ea85f80e01b007cc9b566b8836513bc5102667d833bad4c1092be60fa60c2d4 ./node-v12.18.3.tar.gz
 213d72051a68c37afc37a5d185a4c5bfacc985bc35331024e5f28635f084da70 ./x64/node.lib
 e5224f36cf5ae52ee8532e383142073fd6c28866745e9967992de28cfbf5b63a ./node.lib