CI: Use more explicit check for valid git reference in check actions

.github/actions/check-changes/action.yaml

@@ -38,7 +38,7 @@ runs:
         shopt -s extglob
         shopt -s dotglob
 
-        if ! git cat-file -e ${GIT_BASE_REF}; then
+        if ! git rev-parse --verify ${GIT_BASE_REF} &> /dev/null; then
           echo "::warning::Provided base reference ${GIT_BASE_REF} is invalid"
           if [[ "${USE_FALLBACK}" == 'true' ]]; then
             GIT_BASE_REF='HEAD~1'

.github/actions/qt-xml-validator/action.yaml

@@ -46,7 +46,9 @@ runs:
         shopt -s extglob
         shopt -s globstar
 
-        if (( ! GITHUB_REF_BEFORE )); then GITHUB_REF_BEFORE='4b825dc642cb6eb9a060e54bf8d69288fbee4904'; fi
+        if ! git rev-parse --verify "${GITHUB_REF_BEFORE}" &> /dev/null; then
+          GITHUB_REF_BEFORE='4b825dc642cb6eb9a060e54bf8d69288fbee4904'
+        fi
 
         changes=($(git diff --name-only HEAD~1 HEAD -- UI/forms/**/*.ui))
         case "${GITHUB_EVENT_NAME}" in

.github/actions/run-clang-format/action.yaml

@@ -43,7 +43,9 @@ runs:
         : Run clang-format 🐉
         if (( ${+RUNNER_DEBUG} )) setopt XTRACE
 
-        if (( ! GITHUB_REF_BEFORE )) GITHUB_REF_BEFORE='4b825dc642cb6eb9a060e54bf8d69288fbee4904'
+        if ! git rev-parse --verify ${GITHUB_REF_BEFORE} &> /dev/null; then
+          GITHUB_REF_BEFORE='4b825dc642cb6eb9a060e54bf8d69288fbee4904'
+        fi
 
         local -a changes=($(git diff --name-only HEAD~1 HEAD))
         case ${GITHUB_EVENT_NAME} {

.github/actions/run-cmake-format/action.yaml

@@ -42,7 +42,9 @@ runs:
         : Run cmake-format 🎛️
         if (( ${+RUNNER_DEBUG} )) setopt XTRACE
 
-        if (( ! GITHUB_REF_BEFORE )) GITHUB_REF_BEFORE='4b825dc642cb6eb9a060e54bf8d69288fbee4904'
+        if ! git rev-parse --verify ${GITHUB_REF_BEFORE} &> /dev/null; then
+          GITHUB_REF_BEFORE='4b825dc642cb6eb9a060e54bf8d69288fbee4904'
+        fi
 
         local -a changes=($(git diff --name-only HEAD~1 HEAD))
         case ${GITHUB_EVENT_NAME} {

.github/actions/run-swift-format/action.yaml

@@ -42,7 +42,9 @@ runs:
         : Run swift-format 🔥
         if (( ${+RUNNER_DEBUG} )) setopt XTRACE
 
-        if (( ! GITHUB_REF_BEFORE )) GITHUB_REF_BEFORE='4b825dc642cb6eb9a060e54bf8d69288fbee4904'
+        if ! git rev-parse --verify ${GITHUB_REF_BEFORE} &> /dev/null; then
+          GITHUB_REF_BEFORE='4b825dc642cb6eb9a060e54bf8d69288fbee4904'
+        fi
 
         local -a changes=($(git diff --name-only HEAD~1 HEAD))
         case ${GITHUB_EVENT_NAME} {