ci: fix up Yaml error in specifying constraint on generate step

Failed to quote the expression. Roll on the day we replace this with
CUE!

Again, the trybot test for this will fail because the workflow file at
master on GitHub is broken. But once this CL is merged, all subsequent
builds should pass.

Change-Id: Ie3b1500f64b783bf7f2e316c1cc12961a881117c
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/6066
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

.github/workflows/test.yml

@@ -41,7 +41,7 @@ jobs:
     - name: Generate
       # The Go version corresponds to the precise 1.14.x version specified in
       # the matrix. Skip windows for now until we work out why re-gen is flaky
-      if: matrix.go-version == "1.14.3" && matrix.platform != "windows-latest"
+      if: "matrix.go-version == '1.14.3' && matrix.platform != 'windows-latest'"
       run: go generate ./...
 
     - name: Test

.github/workflows/test_dispatch.yml

@@ -53,7 +53,7 @@ jobs:
     - name: Generate
       # The Go version corresponds to the precise 1.14.x version specified in
       # the matrix. Skip windows for now until we work out why re-gen is flaky
-      if: matrix.go-version == "1.14.3" && matrix.platform != "windows-latest"
+      if: "matrix.go-version == '1.14.3' && matrix.platform != 'windows-latest'"
       run: go generate ./...
 
     - name: Test