logo: reduce sizes of SVG images

curl-logo: 8658 bytes => 4918 bytes
curl-white-symbol: 7682 bytes => 2075 bytes
curl-symbol: 7682 bytes => 2105 bytes

No visual differences. Thanks to https://svgomg.net/

Closes #522

Author: bagder

logo/README.md

@@ -21,7 +21,7 @@ donated to the curl project on May 26 2016.
 | [curl-logo.ai](curl-logo.ai)                 | 1.6MB | vector     | AI              |
 | [curl-logo.jpg](curl-logo.jpg)               | 77K   | 2228 x 852 | JPEG            |
 | [curl-logo.png](curl-logo.png)               | 53K   | 2228 x 852 | PNG             |
-| [curl-logo.svg](curl-logo.svg)               | 8.5K  | vector     | SVG             |
+| [curl-logo.svg](curl-logo.svg)               | 4.9K  | vector     | SVG             |
 | [curl-logo.xcf](curl-logo.xcf)               | 168K  | 2228 x 852 | XCF             |
 | [curl-transparent.png](curl-transparent.png) | 10K   | 1970 x 656 | transparent PNG |
 
@@ -33,7 +33,7 @@ donated to the curl project on May 26 2016.
 |------------------------------------------------------------|------|------------|-----------------|
 | [curl-symbol.jpg](curl-symbol.jpg)                         | 37K  | 789 x 690  | JPEG            |
 | [curl-symbol.png](curl-symbol.png)                         | 24K  | 789 x 690  | PNG             |
-| [curl-symbol.svg](curl-symbol.svg)                         | 7.6K | vector     | SVG             |
+| [curl-symbol.svg](curl-symbol.svg)                         | 2.1K | vector     | SVG             |
 | [curl-symbol.xcf](curl-symbol.xcf)                         | 48K  | 789 x 690  | XCF             |
 | [curl-symbol-transparent.png](curl-symbol-transparent.png) | 3.0K | 683 x 571  | transparent PNG |