feat: add declaration maps and upgrade to rpt2 0.32.1

Basically this combines agilgur5/react-signature-canvas@b14060c and agilgur5/react-signature-canvas@5771d33
- and is based on my upstream fix: ezolenko/rollup-plugin-typescript2@ccd6815

- adds source maps for declarations for consumers
- apparently I left this config out of this repo?
  - I suspect I left it out either because of `@wessberg/rollup-plugin-ts`'s bugs with it or because TSDX previously had bugs with it
    - c.f. ezolenko/rollup-plugin-typescript2#221 and the worse downstream version I had written first: jaredpalmer/tsdx#488

- Previously, I ran into a bug in rpt2 when using it as a `configPlugin` and enabling `declarationMap`s
  - that bug was actually due to some code _I_ wrote in rpt2 and an edge case I didn't know existed (`configPlugin` usage means Rollup has no `output`)
  - so I eventually fixed it myself too
  - and in the past month I stepped up to help maintain rpt2 and fixed a ton of issues and improved lots of things per the release notes :)

Author: agilgur5

package-lock.json

@@ -74,7 +74,7 @@
     "package-json-type": "^1.0.3",
     "rollup": "^2.70.1",
     "rollup-plugin-terser": "^7.0.2",
-    "rollup-plugin-typescript2": "^0.31.2",
+    "rollup-plugin-typescript2": "^0.32.1",
     "ts-node": "^10.7.0",
     "typescript": "^4.4.0"
   }

package.json

@@ -9,6 +9,8 @@
     "outDir": "dist/",
     // output .d.ts declaration files for consumers
     "declaration": true,
+    // output .d.ts.map declaration map files for consumers
+    "declarationMap": true,
     // output .js.map sourcemap files for consumers
     "sourceMap": true,
     // use Node's module resolution algorithm, instead of the legacy TS one