ci: Fix composite action syntax error

Author: stackotter

.github/actions/compile-docs/action.yml

@@ -19,7 +19,7 @@ runs:
   using: "composite"
   steps:
     - name: Compile documentation (with SwiftPM)
-      if: ${{ inputs.xcodebuild != true }} # Compare to constant to treat empty input as false
+      if: ${{ inputs.xcodebuild != 'true' }} # Compare to constant to treat empty input as false
       run: |
         set -ex
         mkdir "$TARGET.doccarchive" && \
@@ -39,7 +39,7 @@ runs:
       env:
         TARGET: ${{ inputs.target }}
     - name: Compile documentation (with xcodebuild)
-      if: ${{ inputs.xcodebuild == "true" }} # Compare to constant to treat empty input as false
+      if: ${{ inputs.xcodebuild == 'true' }} # Compare to constant to treat empty input as false
       run: |
         set -ex
         destination=""
@@ -57,7 +57,7 @@ runs:
         TARGET: ${{ inputs.target }}
         DEVICE_TYPE: ${{ inputs.xcodebuild-device-type }}
     - uses: actions/upload-artifact@v4
-      if: ${{ inputs.upload == true }} # Compare to constant to treat empty input as false
+      if: ${{ inputs.upload == 'true' }} # Compare to constant to treat empty input as false
       with:
         name: ${{ inputs.target }}.doccarchive
         path: ${{ inputs.target }}.doccarchive