ci: test interesting revs: target spec changes, glam semver breakage (by us)

Author: Firestar99

.github/workflows/push.yaml

@@ -56,6 +56,41 @@ jobs:
             glam-version: 0.24.2
           - rust-gpu-version: 0.9.0
             glam-version: 0.24.2
+
+          # target spec introduction
+          # last version before
+          # * fails: compiler too old, `serde` using `#[diagnostic]`
+#          - rust-gpu-version: cc752312c3de6813a41189e46476d5c1be5e0bbe
+#            glam-version: 0.30.7
+          # first version requiring target specs
+          # * fails: target spec mismatch!
+          # * resolution: Since this is just a few commits, I'd be fine ignoring it.
+#          - rust-gpu-version: 02cefd101014f66b79dffb20a2c2b5b7c9038401
+#            glam-version: 0.30.7
+          # target specs change again just a few commits later
+          # * fails: compiler too old, `proc-macro2` using `Literal::byte_character`.
+          # * resolution: want to support, can't be bothered to hack in old proc-macro2 versions
+#          - rust-gpu-version: bbb61f58b3d24f3f64745050eb214b90bf6dcce9
+#            glam-version: 0.30.7
+
+          # testing rustc 1.5 months later
+          - rust-gpu-version: eea8998df9dc2fd8e7a65c5b5b7ae20c238a665a
+            glam-version: 0.29.3
+
+          # just after target specs v2 refactor, we updated to rustc 1.85 and needed to change them again
+          # before
+          - rust-gpu-version: a547c6e45266d613d9fec673e869d7a96181e47b
+            glam-version: =0.30.7
+          # after
+          - rust-gpu-version: 2326b87fe1542eeb898065e36ac949307b55386d
+            glam-version: =0.30.7
+
+          # glam semver breakage due to vector type refactor
+          # before, glam was fixed to <=0.30.7 in this commit
+          - rust-gpu-version: f79c4181a5dc2d37303947b113f190930c6c1ce6
+            glam-version: =0.30.7
+          # after, glam >0.30.8
+          - rust-gpu-version: e767f24f2565baf1a71bbaf84d453d181cab2417
     runs-on: ubuntu-latest
     env:
       RUST_LOG: debug