Specify serde_json, log, chrono versions further to keep msrv guarantee

Cargo.toml

@@ -23,7 +23,7 @@ urlencoding = { version = "2.1.0", optional = true }
 punycode = { version = "0.4.1", optional = true }
 # For the json-using-serde feature:
 serde = { version = "1.0.101", optional = true }
-serde_json = { version = "1.0.41", optional = true }
+serde_json = { version = ">=1.0.0, <1.0.101", optional = true } # this range works with the 1.48 MSRV
 # For the proxy feature:
 base64 = { version = "0.12", optional = true }
 # For the https features:
@@ -33,12 +33,14 @@ once_cell = { version = "1.14.0", optional = true }
 webpki-roots = { version = "0.25.2", optional = true }
 rustls-webpki = { version = "0.101.4", optional = true }
 openssl = { version = "0.10.29", optional = true }
-log = { version = "0.4.5" }
+log = { version = ">=0.4.0, <0.4.19" }  # this range works with the 1.48 MSRV
 openssl-probe = { version = "0.1", optional = true }
 native-tls = { version = "0.2", optional = true }
 
 [dev-dependencies]
 tiny_http = "0.8.2"
+# (tiny_http dependency) this range works with the 1.48 MSRV
+chrono = ">=0.4.0, <0.4.24"
 
 [package.metadata.docs.rs]
 features = ["json-using-serde", "proxy", "https", "punycode"]