Shrink tiktok.svg by 51 bytes. (#538)

* Update tiktok.svg

Shrink 51 bytes (484 => 433 bytes). 
The path wasn't optimized, nor the colors.

* Update README.md

Update the tiktok.svg size (433 bytes).

README.md

@@ -38,7 +38,7 @@ Say thanks!
 <tr>
 <td>dev.to<br><img src="https://edent.github.io/SuperTinyIcons/images/svg/dev_to.svg" width="125" title="dev.to"/><br>623 Bytes</td>
 <td>Goodreads<br><img src="https://edent.github.io/SuperTinyIcons/images/svg/goodreads.svg" width="125" title="Goodreads"/><br>669 Bytes</td>
-<td>TikTok<br><img src="https://edent.github.io/SuperTinyIcons/images/svg/tiktok.svg" width="125" title="TikTok"/><br>484 Bytes</td>
+<td>TikTok<br><img src="https://edent.github.io/SuperTinyIcons/images/svg/tiktok.svg" width="125" title="TikTok"/><br>433 Bytes</td>
 <td>Friendica<br><img src="https://edent.github.io/SuperTinyIcons/images/svg/friendica.svg" width="125" title="Friendica"/><br>849 Bytes</td>
 </tr>
 </table>

images/svg/tiktok.svg

@@ -2,4 +2,4 @@
 aria-label="TikTok" role="img"
 viewBox="0 0 512 512"><rect
 rx="15%" height="512" width="512"
-fill="#fff"/><defs><path id="t" d="m 219,200 a 117,117 0 1 0 100.6,115.4 v -128 a 150,150 0 0 0 88,28 v -63 a 88,88 0 0 1 -88,-88 H 256 V 316 a 53.5,53.5 0 1 1 -37,-51 z" style="mix-blend-mode:multiply"/></defs><use href="#t" fill="#ff004f" transform="translate(18,15)"/><use href="#t" fill="#00f2ea"/></svg>
+fill="#fff"/><defs><path id="t" d="M219 200a117 117 0 1 0 101 115v-128a150 150 0 0 0 88 28v-63a88 88 0 0 1-88-88h-64v252a54 54 0 1 1-37-51z" style="mix-blend-mode:multiply"/></defs><use href="#t" fill="#f05" x="18" y="15"/><use href="#t" fill="#0ee"/></svg>