Make egui work on WebGPU out of the box. (#2945)

* Make wgpu webgl/gles opt-in (but still work out of the box via feature flag), workaround canvas creation issue

* missing allow unsafe code annotations

* add breaking change not to eframe release notes

* Add --webgpu flag to build_demo_web.sh

* Improve CHANGELOG docs

* Clean up, and prepare for having to wasm:s

* put canvas without workaround under `if false`

* fix spelling

---------

Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>

Cargo.lock

@@ -921,12 +921,6 @@ dependencies = [
  "typenum",
 ]
 
-[[package]]
-name = "cty"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b365fabc795046672053e29c954733ec3b05e4be654ab130fe8f1f94d7051f35"
-
 [[package]]
 name = "custom_3d_glow"
 version = "0.1.0"
@@ -2948,12 +2942,9 @@ checksum = "63e935c45e09cc6dcf00d2f0b2d630a58f4095320223d47fc68918722f0538b6"
 
 [[package]]
 name = "raw-window-handle"
-version = "0.5.0"
+version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ed7e3d950b66e19e0c372f3fa3fbbcf85b1746b571f74e0c2af6042a5c93420a"
-dependencies = [
- "cty",
-]
+checksum = "f2ff9a1f06a88b01621b7ae906ef0211290d1c8a168a15542486a8f61c0833b9"
 
 [[package]]
 name = "rctree"