new attribute interpreter for commands (#7)

.ci/gotenberg.yml

@@ -17,12 +17,15 @@ commands:
   # Unlike others commands' templates, you have access to FilesPaths instead of FilePath: it gathers all PDF files which should be merged.
   merge:
     template: "pdftk {{ range $filePath := .FilesPaths }} {{ $filePath }} {{ end }} cat output {{ .ResultFilePath }}"
+    interpreter: "/bin/sh -c"
     timeout: 30
   
   conversions:
 
       # The command template: you have access to FilePath and ResultFilePath variables.
     - template: "markdown-pdf {{ .FilePath }} -o {{ .ResultFilePath }}"
+      # The binary which will call the command.
+      interpreter: "/bin/sh -c"
       # Duration in seconds after which the command will be killed if it has not finished.
       timeout: 30
       # Files with the following extensions will be converted by the current command.
@@ -30,12 +33,14 @@ commands:
         - ".md"
 
     - template: "xvfb-run -e /dev/stdout wkhtmltopdf {{ .FilePath }} {{ .ResultFilePath }}"
+      interpreter: "/bin/sh -c"
       timeout: 30
       extensions:
         - ".html"
         - ".htm"
 
     - template: "unoconv --format pdf --output \"{{ .ResultFilePath }}\" \"{{ .FilePath }}\""
+      interpreter: "/bin/sh -c"
       timeout: 30
       extensions:
         - ".doc"