Fix: enable 'inlineSources' on tsconfig.json

[kajikentaro]

Issue

If we use this library, following error occur.
The reason is that the source map don't have the field sourcesContent and the file which is mentioned in sources field.

WARNING in ./node_modules/http-status-ts/esm/HttpMethod.js
Module Warning (from ./node_modules/source-map-loader/dist/cjs.js):
Failed to parse source map from '/home/aaa/project-name/node_modules/src/HttpMethod.ts' file: Error: ENOENT: no such file or directory, open '/home/aaa/project-name/node_modules/src/HttpMethod.ts'

Modification

This PR enable inlineSources option and update to include sourcesContent in output source maps.

ie) build/cjs/HttpMethod.js.map

AS-IS

{"version":3,"file":"HttpMethod.js","sourceRoot":"","sources":["../../src/HttpMethod.ts"],"names":[],"mappings":";;;AAAA,IAAY,UASX;AATD,WAAY,UAAU;IAClB,yBAAW,CAAA;IACX,2BAAa,CAAA;IACb,yBAAW,CAAA;IACX,+BAAiB,CAAA;IACjB,iCAAmB,CAAA;IACnB,iCAAmB,CAAA;IACnB,6BAAe,CAAA;IACf,6BAAe,CAAA;AACnB,CAAC,EATW,UAAU,0BAAV,UAAU,QASrB"}

TO-BE

{"version":3,"file":"HttpMethod.js","sourceRoot":"","sources":["../../src/HttpMethod.ts"],"names":[],"mappings":";;;AAAA,IAAY,UASX;AATD,WAAY,UAAU;IAClB,yBAAW,CAAA;IACX,2BAAa,CAAA;IACb,yBAAW,CAAA;IACX,+BAAiB,CAAA;IACjB,iCAAmB,CAAA;IACnB,iCAAmB,CAAA;IACnB,6BAAe,CAAA;IACf,6BAAe,CAAA;AACnB,CAAC,EATW,UAAU,0BAAV,UAAU,QASrB","sourcesContent":["export enum HttpMethod {\r\n    GET = \"GET\",\r\n    POST = \"POST\",\r\n    PUT = \"PUT\",\r\n    DELETE = \"DELETE\",\r\n    CONNECT = \"CONNECT\",\r\n    OPTIONS = \"OPTIONS\",\r\n    TRACE = \"TRACE\",\r\n    PATCH = \"PATCH\"\r\n}\r\n"]}