Auto merge of #12741 - changm:shader, r=ConnorGBrewster

update servo to use webrender shaders

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Pulls shaders from webrender and update the webrender commit.
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- [ X] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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components/servo/Cargo.lock

@@ -2554,7 +2554,7 @@ dependencies = [
 [[package]]
 name = "webrender"
 version = "0.1.0"
-source = "git+https://github.com/servo/webrender#eebe599cab295271900d7fbbe3017232dcbba867"
+source = "git+https://github.com/servo/webrender#66b7134918a56c561cbdf72ab284f5da83459ec4"
 dependencies = [
  "app_units 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "bit-set 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",