feat(i18n): added i18next for user interface translations (#432)

src/components/DetailSidebar/DetailSidebarFundButton.tsx

@@ -1,6 +1,7 @@
 import React, { useContext } from 'react';
 import styled from '@emotion/styled';
 import Favorite from '@material-ui/icons/Favorite';
+import { Trans } from 'react-i18next';
 
 import Button from '../../muiComponents/Button';
 import Link from '../Link';
@@ -38,8 +39,7 @@ const DetailSidebarFundButton: React.FC = () => {
   return (
     <StyledLink external={true} to={fundingUrl}>
       <Button color="primary" fullWidth={true} startIcon={<StyledFavoriteIcon />} variant="outlined">
-        <StyledFundStrong>{'Fund'}</StyledFundStrong>
-        {'this package'}
+        <Trans components={[<StyledFundStrong key="fund" />]} i18nKey="button.fund-this-package" />
       </Button>
     </StyledLink>
   );

src/components/DetailSidebar/DetailSidebarTitle.tsx

@@ -1,5 +1,6 @@
 import React from 'react';
 import styled from '@emotion/styled';
+import { useTranslation } from 'react-i18next';
 
 import Box from '../../muiComponents/Box';
 import Heading from '../../muiComponents/Heading';
@@ -21,12 +22,17 @@ const StyledBoxVersion = styled(Box)<{ theme?: Theme }>(({ theme }) => ({
   color: theme && theme.palette.text.secondary,
 }));
 
-const DetailSidebarTitle: React.FC<Props> = ({ description, packageName, version, isLatest }) => (
-  <Box className={'detail-info'} display="flex" flexDirection="column" marginBottom="8px">
-    <StyledHeading>{packageName}</StyledHeading>
-    {description && <div>{description}</div>}
-    <StyledBoxVersion>{`${isLatest ? 'Latest v' : 'v'}${version}`}</StyledBoxVersion>
-  </Box>
-);
+const DetailSidebarTitle: React.FC<Props> = ({ description, packageName, version, isLatest }) => {
+  const { t } = useTranslation();
+  return (
+    <Box className={'detail-info'} display="flex" flexDirection="column" marginBottom="8px">
+      <StyledHeading>{packageName}</StyledHeading>
+      {description && <div>{description}</div>}
+      <StyledBoxVersion>
+        {isLatest ? t('sidebar.detail.latest-version', { version }) : t('sidebar.detail.version', { version })}
+      </StyledBoxVersion>
+    </Box>
+  );
+};
 
 export default DetailSidebarTitle;