Install referenced schema in "npm:validate" task

The "npm:validate" task validates the repository's `package.json` npm manifest file against its JSON schema to catch any
problems with its data format.

In order to avoid duplication of content, JSON schemas may reference other schemas via the `$ref` keyword. The
`package.json` schema was recently updated to share resources with the "base" configuration schema, which caused the
validation to start failing:

schema /tmp/package-json-schema-m3x8Uu4NED.json is invalid
error: can't resolve reference https://json.schemastore.org/base.json#/definitions/license from id https://json.schemastore.org/package.json#

The solution is to configure the task to download that schema as well and also to provide its path to the avj-cli
validator via a `-r` flag.

Author: per1234

Taskfile.yml

@@ -188,6 +188,10 @@ tasks:
       AVA_SCHEMA_URL: https://json.schemastore.org/ava.json
       AVA_SCHEMA_PATH:
         sh: task utility:mktemp-file TEMPLATE="ava-schema-XXXXXXXXXX.json"
+      # Source: https://github.com/SchemaStore/schemastore/blob/master/src/schemas/json/base.json
+      BASE_SCHEMA_URL: https://json.schemastore.org/base.json
+      BASE_SCHEMA_PATH:
+        sh: task utility:mktemp-file TEMPLATE="base-schema-XXXXXXXXXX.json"
       # Source: https://github.com/SchemaStore/schemastore/blob/master/src/schemas/json/eslintrc.json
       ESLINTRC_SCHEMA_URL: https://json.schemastore.org/eslintrc.json
       ESLINTRC_SCHEMA_PATH:
@@ -224,6 +228,7 @@ tasks:
     cmds:
       - wget --quiet --output-document="{{.SCHEMA_PATH}}" {{.SCHEMA_URL}}
       - wget --quiet --output-document="{{.AVA_SCHEMA_PATH}}" {{.AVA_SCHEMA_URL}}
+      - wget --quiet --output-document="{{.BASE_SCHEMA_PATH}}" {{.BASE_SCHEMA_URL}}
       - wget --quiet --output-document="{{.ESLINTRC_SCHEMA_PATH}}" {{.ESLINTRC_SCHEMA_URL}}
       - wget --quiet --output-document="{{.JSCPD_SCHEMA_PATH}}" {{.JSCPD_SCHEMA_URL}}
       - wget --quiet --output-document="{{.NPM_BADGES_SCHEMA_PATH}}" {{.NPM_BADGES_SCHEMA_URL}}
@@ -237,6 +242,7 @@ tasks:
           --all-errors \
           -s "{{.SCHEMA_PATH}}" \
           -r "{{.AVA_SCHEMA_PATH}}" \
+          -r "{{.BASE_SCHEMA_PATH}}" \
           -r "{{.ESLINTRC_SCHEMA_PATH}}" \
           -r "{{.JSCPD_SCHEMA_PATH}}" \
           -r "{{.NPM_BADGES_SCHEMA_PATH}}" \