fix production build errors

vocodes/src/App.tsx

@@ -42,7 +42,7 @@ class App extends React.Component<Props, State> {
   setSpeakerBySlug = (speakerSlug: string) : void => {
     console.log('speaker', speakerSlug);
     SPEAKERS.forEach(speaker => {
-      if (speaker.slug == speakerSlug) {
+      if (speaker.slug === speakerSlug) {
         this.setState({ speaker: speaker });
       }
     })

vocodes/src/modes/speak/Avatar.tsx

@@ -20,7 +20,7 @@ class Avatar extends React.Component<Props, State> {
     const source = `https://via.placeholder.com/300x300/FF0000/FFFFFF?text=${this.props.currentSpeaker.getSlug()}`;
     return (
       <div>
-        <img src={source} />
+        <img src={source} alt="speaker image" />
       </div>
     );
   }

vocodes/src/modes/speak/Form.tsx

@@ -3,7 +3,8 @@ import React from 'react';
 import { SpeakRequest } from './SpeakRequest';
 import { Speaker } from '../../Speakers';
 import { createColorMap, linearScale } from "@colormap/core";
-import { VIRIDIS, CIVIDIS, PLASMA, INFERNO, MAGMA, BLACK_WHITE,  } from "@colormap/presets";
+//import { VIRIDIS, CIVIDIS, PLASMA, INFERNO, MAGMA, BLACK_WHITE,  } from "@colormap/presets";
+import { MAGMA } from "@colormap/presets";
 
 class Spectrogram {
   pixels: Uint8ClampedArray;